Making acoustic systems with your own hands. Making a mini speaker with an amplifier How to make a homemade speaker at home

Do-it-yourself shelf acoustics

DIY or DIY

Once I decided to assemble myself high-quality acoustics for sounding small room, as well as for use as near-field monitors when working with sound on a computer (hobby). The main requirement is an adequate sound in relation to the source. Not so that “the bottoms are sausage” or “cymbals rang”, but an adequate natural sound. So, we collect high-quality "shelf speakers".

Number of lanes

In theory, the ideal system is single-lane. But, like everything ideal, such a system does not exist in nature. Yes, the same Vizaton has very high-quality broadband speakers, but for some reason all well-known manufacturers make two-way shelf systems. And when it comes to floor version, then 3 bands are not uncommon. There was no particular question here - the classic two-band version: bass and treble.

Speaker selection

The main requirement for speakers is an optimal price / quality ratio. Those. it should not be "cheap" for 500 rubles, but not a mind-blowing "high-end" for $1000. Besides, I wasn't in a hurry. Thought to collect with my own hands“Shelf speakers” came a long time ago, and I threw a bait in advance to my good friend, “sick” sound, with which we have been constantly and fruitfully communicating on this topic for a long time.

The first to appear were HF - Vifa XT19SD-00/04 ring-rad. These are high quality 4 ohm tweeters, quite popular among audiophiles. They were planned for one set, but for some reason they did not go and ended up in my set.

LF arrived second. They turned out to be very decent midbasses from the Soundstream Exact 5.3 kit. Here you can read a little about them. It so happened that the “tweeters” burned out during installation, and the lone woofers were not needed by themselves. 4-ohm 5.5" midbasses, mounted in a die-cast aluminum basket, were immediately purchased.

Now that you have speakers, you can start creating acoustics.

Active / passive?

Each option has its pros and cons. First, you need to take into account the compactness of the speakers themselves and the associated difficulties in layout in a limited space. And it makes no sense to mount outside. Secondly, individual modules like independent components can be combined in the future, and also easier to repair in which case. And thirdly, active speakers are quite expensive. Because if you make a decent amplifier (and sometimes one in each case), then it will turn out to be more expensive than the acoustics themselves. Besides, I already had an amplifier. But in any case, I am for the scheme - passive acoustics + amplifier, it is more versatile.

Hull size calculation

We have decided on the speakers, now we need to understand which case is optimal for them. Dimensions are calculated based on the sound characteristics of the woofer. There are no recommendations on the manufacturer's website, because. The speaker was intended primarily for car audio. There is no point in keeping special equipment for these purposes, unless it is your job. Therefore, an intelligent dude with a special stand comes to the rescue. As a result of laboratory tests, we obtain the estimated case size of 310 x 210 x 270 mm. During the measurements, the parameters of the phase inverter were also calculated.

By the way, many manufacturers publish recommended cabinet sizes for speakers on their websites. When such information is available, it is logical to use it, but in this case I did not have such data, so I had to do laboratory research.

Housing material

In my opinion, the most optimal material for the body is MDF. It is acoustically neutral and also slightly better in performance than chipboard. Plywood is also good, but find quality plywood not easy, and it is more expensive and more difficult to process. A 22mm MDF sheet was chosen as the starting material for the body. In principle, the standard 18-20mm is enough, but I decided to do a little with a margin. Rigidity is not superfluous.

Housing construction and design

One of the most milestones. Before going for MDF, I advise you to decide on the design in order to immediately ask the seller to cut the sheet in parts, and at a normal point of sale there are always good machines with accurate and even cuts. At home, such a cut is difficult to obtain.

So, design. The speakers should look at least as good as the "industrial" ones, so that there is no feeling of a club of crazy hands. After all, we make not only high-quality, but also beautiful acoustics. In general, there are practically no beautiful, interesting and at the same time structurally simple acoustic systems. Beautiful acoustics are made by the Italian Sonus Faber, stunning in beauty - Magico Mini. But they are all made using precision machines, which, by definition, are not at home. Alternatively, you can order cases to a good "cabinet maker" with hands and CNC. Such work will cost, depending on where and what you order, from 10,000 rubles. up to 30 000 rub. along with materials. If the specialist is good, then the columns will look no worse, or even better than the “store” ones. In this case, I decided that I would do everything myself. Therefore, we look at things realistically and make a design without any bevels, curly cuts etc. Those. it will be a parallelepiped. The calculated dimensions give a rather pleasant proportion, and the proportion in design is already half the battle.

What to design? Although I am connected with design by occupation, I know 3D packages, to put it mildly, superficially. At the same time, the program should be more engineering than rendering. Specialized "Kadas" for this purpose are too heavy and unnecessary. The solution was quickly found - freeware SketchUp is more than suitable for this purpose. It is so simple and intuitive that it was fully mastered in about an hour. He can do the main thing: quickly create any shapes, set dimensions, use simple textures. I think that such a program is ideal for "home" purposes. In it, you can easily, for example, design a kitchen or even a small house.

Here is the body structure:

Based on the drawing, a diagram of cutting the sheet emerges:

In general, the options are good appearance, but purely constructively cause difficulties. As a result, it was decided side walls trim with ash veneer, and cover the remaining 4 walls around the circumference with leather, more precisely with high-quality automotive leatherette. The pishchal is beautiful in itself, but the woofer has a constructive overlay on the front side of the case, which will not look very nice. Therefore, it was decided to make an additional decorative overlay (ring) for it, which will press it to the body, and at the same time add beauty to the column itself. We decided on the design and construction.

Tools

Before moving on to the next step, I will outline what basic tools are needed for the job:

Circular.

Electric jigsaw.

Grinder.

Straight arms.

Without this set, it is better to order cases from a good craftsman.

saw cut

So, we cut the budget sheet of MDF. I already wrote that it is better to saw on special machines - it's inexpensive, but it turns out exactly. But since I decided to make the case myself inside and out, then for the purity of the experiment I sawed it myself manual circular, and small pieces of a jigsaw with a guide. As expected perfect cut Did not work out. After cutting, pairs of walls (left-right, front-back, etc.) are installed in pairs, adjusted with a grinder and / or an electric planer and checked for perpendicularity with a square. And in the future, during assembly, they are finally adjusted after gluing. Loss of 2-3 mm is insignificant. But still, I recommend sawing immediately “at the base”, save a lot of time.

Case assembly

The walls are glued with PVA and tightened with screws. First, we glue the case without the front wall.

Now there is a hole for the terminal block, as well as a chamfer in order to “drown” it. Initially, according to the project, the terminal block was supposed to be placed below. But in the process, it became clear that mounting the crossover in the center through the hole for the woofer would not be very convenient, so I moved the hole for the terminal block higher, and the place for the crossover lower.

You can close the box.

Now one of the very important stages is cutting holes for the speakers on the front panel. I already said it's perfect. acoustic system- It's single lane. Why? Because the propagation of sound goes from one source to the listener without a mismatch in time due to the difference (negligible) in the distance, which is when using a multi-band system. Therefore, the speakers are best placed as close to each other as possible. So the sound picture is "dense". We calculate the holes so that the distance between the edges of the speakers will be approximately 1 cm. The holes are sawn with a jigsaw with a circular guide.

After the chamfers are removed, we apply the terminal block and speakers, after which we drill holes for future self-tapping screws with a thin drill. Without them, firstly, the MDF itself can “spread out” when screwing in the screws, and secondly, it will be more difficult to place the speakers evenly during the final installation. For a very long time I thought about how to set the speakers relative to each other, I came to this scheme:

Screw holes on exterior surfaces must be repaired before final finishing. I used epoxy. In order not to wait until one surface hardens, I sealed each surface with adhesive tape and took on the next. When the epoxy was dry, I went through the grinder.

The veneer needs to be protected. I covered it with clear yacht varnish.

Now you need to fit the body with leatherette. There are many options for how to do this. I decided to do the following. A strip is cut 20 mm larger than the body width and slightly longer than the body circumference. On each side it is folded by 10 mm, the hem is glued to the "special glue 88". Then, on the same glue, the strip is glued around the circumference to the body. First the bottom (partially), then the back wall, then the top, then the front and again the bottom. On last step before gluing, the strip is cut in place and glued end-to-end. I glued all sides at once, i.e. didn't wait for each side to dry. After each side, I took a short pause (the glue sticks quickly enough), and started on the next one.

If you really want to, then you can somehow ennoble the fazik.

Then holes are cut on the terminal block, "woofer" and "tweeter". The skin on the terminal block and HF will sink down, so the cutout diameter can be left 5-10 mm smaller. The skin on the bass will be pressed against the decorative ring, so you need to cut it so that it is not visible.

Final editing

First of all, we mount the crossover. Cross - self-made, on a good elemental base. Air core coils, tweeter film capacitors and MOX resistors are used. I didn’t solder it myself, but I ordered sensible guys.

Now we solder the desired pair of wires to the terminal block and fix it on the case. The terminal block and speakers are screwed with decorative black self-tapping screws with an asterisk head. The overlay on the “squeaks” is screwed with similar self-tapping screws, so it would be logical to use the same for the rest. Back wall ready.

Midbass must be slipped under the skin, and pressed down with a decorative ring from above. Solder the remaining pair of wires and mount the speaker.

All? All. We fasten the speaker cable to the terminal block and begin testing.

Tests

The system was tested in the following configurations:

1. Receiver Sherwood VR-758R + acoustics.

2. Computer + Unicorn (USB-DAC) + Self-made stereo amplifier + acoustics.

3. Computer + E-mu 0204 (USB-DAC) + Sherwood VR-758R + acoustics.

A little about the configurations themselves. I personally think that at the moment perfect option home music center is: computer + USB-DAC + amplifier + acoustics. The sound in the digital without distortion is removed via USB and fed to a high-quality DAC, from which it is transmitted to a high-quality amplifier and then to acoustics. In such a chain, the amount of distortion is minimal. In addition, you can use completely different backing tracks: 44000/16, 48000/24, 96000/24, etc. Everything is limited by the capabilities of the driver and DAC. Receivers in this regard are less flexible and obsolete in advance. The size of modern hard drives allows you to store almost the entire media library on them. And the tendency to subscribe to Internet content may abolish this option, although this is not the near future and is far from suitable for everyone.

I will say right away that in all three configurations the acoustics sounded great. To be honest, I didn't even expect it. Here are some subjective aspects.

1. Adequate and natural sound. What is recorded is reproduced. There are no twists in any direction. As I wanted.

2. Greater sensitivity to the source material. All flaws in the sound recording, if any, are clearly audible. High-quality mixed tracks listen perfectly.

3. Well-readable basses for such sizes. Of course, you can't fully appreciate organ music on bookshelves (it's hard to appreciate it on acoustics in general), but most of the material can be "digested" without problems. It is difficult to expect more from such babies.

4. Very good detail work. Every instrument is heard. Even with a rich sound image and a decent volume, the sound does not go into mush (the amplifier plays an important role here).

5. I want to make it louder;) Ie. acoustics does not yell, but plays smoothly. Although there is also no small merit of the amplifier itself, because. as the load increases, a good amplifier maintains linearity.

6. From long listening does not hurt the head. For me personally, this often happens, but here he plays all day and at least something.

7. Fears about the incorrect panorama and strong dependence of the sound on the position of the listener were not confirmed. As far as I know, car acoustics have a specific sound phasing due to the location of the speakers in the cabin. Namely, I read about this kit that its midbasses are more universal in this regard. Which is actually confirmed. You can sit in the center in front of the speakers, you can stand next to them sideways - the sound is excellent. There is a relationship, but it is very small.

As for the configurations themselves, the best sound quality was achieved with the second configuration.

First, a very high quality Unicorn DAC was used.

Secondly, the "self-made amplifier" is the know-how of one sensible Togliatti "sound player". Here it is in a nice little aluminum case:

In a nutshell, we managed to find a circuit solution in which the amplifier retains its characteristics when the volume changes, i.e. does not distort the sound at any (structurally permissible) volume. A lot of amplifiers (even very expensive ones) suffer from this. It was amazing to listen to how such an amplifier brought many loudspeakers to life, i.e. made them sound like they should sound. By the way, some industrial amplifiers were also redesigned according to this scheme (in particular, quite good Xindak itself), and they had a “second wind”.

Compare acoustics with something else, you ask? Yes, for example, with the ProAC Studio 110, these are quite high-quality bookshelf acoustics, here's a little about them. Compared, realized that they sound exactly no worse. The “proaks” may have a slightly lesser dependence of the sound on the position of the listener due to the specific placement of the inverter and the “tweeter”, where they somehow cleverly calculated all this. And the rest is absolutely no worse, even I personally liked my homemade products more, but we’ll write it down to subjectivity;) I also put on headphones (quite good Koss) and compared by panorama, tops and bottoms. Absolutely identical sound. Even downstairs. In general, the delight is complete.

Material Costing

Mid/bass speakers (pair): 3 000 rub.

Tweeters (pair): 3 000 rub.

Crossover (pair): 3 000 rub.

Sintepon: 160 rub.

Terminal (terminal block): 700 rub.

Screws: 80r.

MDF sheet, 22mm: 2 750r.

Scotch tape: 30 rub.

PVA: 120 rub.

Special glue 88: 120 rub.

Vibration isolation: 200 rub.

Figured ring-lining: 500 rub.

Cable: 500r.

Total: 14 160 rubles.

Some materials were or got free of charge, respectively, are not taken into account here.

In custody

In any more or less complex device or complete functional system, absolutely everything is important. When it comes to a musical system, the final result is influenced by a large number of factors:

Soundtrack quality.

A device for playing a phonogram.

Digital-to-analog converter.

Signal amplifier.

Wires.

Speakers installed in the speaker cabinet.

Properly designed for speakers and high-quality assembled cases.

Scheme and kit for a crossover.

This is a basic but not complete list.

It is wrong to assume that the main thing is the amplifier or the main thing is the wires, or the main thing is the speakers. A home music system is like an orchestra. And if in this orchestra someone will be bad, and someone will play brilliantly, then in general it will turn out - average. Or, as a very precise example said: if you mix a barrel of shit with a barrel of jam, you get two barrels of shit.

There is another extreme. Good system costs fabulous money. So each component should cost half a million. And phonograms should be exclusively in Super Audio CD or on branded records. Like a closed society of elite audiophiles. Bullshit is everything.

I came to the conclusion that to assemble my own relatively budget system, which is described by the single word “Sounds”, is quite possible. And if as a DAC or amplifier, due to its peculiarities, it is better to use real-life solutions, which are now very numerous. Then a properly made (independently or on order) speaker system will sound better than a “branded” one purchased for the same money. Almost all components can now be ordered online. Moreover, many manufacturers publish enclosure diagrams for the corresponding speakers. There is a mass software for calculating the parameters of the hulls. There are many specialized forums on the network, and offline there are people with hands. Of course, it is impossible to be an expert in everything. As in any field, the main thing is to know the general principles.

The article does not claim to be the ultimate truth, but I hope that my thoughts and my experience will be useful to someone else.
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Do sound speakers with their own hands - this is where many begin their passion for a complex, but very interesting thing - the technique of sound reproduction. Economic considerations often become the initial motivation: the prices for branded electro-acoustics are overstated, not excessively - ugly arrogantly. If the sworn audiophiles, who do not skimp on rare radio tubes for amplifiers and flat silver wire for winding audio transformers, complain on the forums that the prices for acoustics and speakers for it systematically swell, then the problem is really serious. Do you want speakers for the house for 1 million rubles. pair? Please, there are more expensive ones. That's why The materials in this article are designed primarily for the very, very beginners: they need to quickly, simply and inexpensively make sure that the creation of their own hands, for which everything took dozens of times less money than for a “cool” brand, can “sing” no worse, or at least comparable. But probably, some of the foregoing will be a revelation for the masters of amateur electroacoustics- if it is honored by reading them.

Speaker or speaker?

A sound column (KZ, sound column) is one of the types of acoustic design of electrodynamic loudspeaker heads (GG, speakers), designed for technical and information sounding of large public spaces. In general, the acoustic system (AS) consists of a primary sound emitter (FROM) and its acoustic design, which provides the required sound quality. Home speakers are for the most part similar in appearance to loudspeakers, which is why they are nicknamed. Electroacoustic systems (EAS) also include an electrical part: wires, terminals, crossover filters, built-in audio frequency power amplifiers (UMZCH, in active speakers), computing devices (in speakers with digital channel filtering), etc. Acoustic design of household speakers is usually located in the body, which is why they look like more or less elongated columns.

Acoustics and electronics

The acoustics of an ideal speaker is excited over the entire audible frequency range of 20-20,000 Hz with one broadband primary IZ. Electroacoustics is slowly but surely moving towards the ideal, however top scores still show speakers with frequency division into channels (bands) LF (20-300 Hz, low frequencies, bass), MF (300-5000 Hz, medium) and HF (5000-20,000 Hz, high, top) or LF- MF and HF. The first, of course, are called 3-way, and the second - 2-way. It is best to start mastering electroacoustics with 2-way speakers: they allow you to get sound quality up to high Hi-Fi (see below) inclusive at home without unnecessary costs and difficulties. The sound signal from the UMZCH or, in active speakers, low-power from the primary source (player, computer sound card, tuner, etc.) is distributed over the frequency channels by crossover filters; this is called channel defiltering, like crossover filters themselves.

The remainder of the article focuses primarily on how to make speakers that provide good acoustics. The electronic part of electroacoustics is a subject of special serious discussion, and not just one. Here it should only be noted that, firstly, at first it is not necessary to take on digital filtering that is close to ideal, but complex and expensive, but to apply passive filtering on inductive-capacitive filters. For a 2-way speaker, you need only one plug of low-pass/high-pass crossover filters (LPF/HPF).

There are special programs for the calculation of separation ladder filters AC, for example. JBL Speaker Shop. However, at home customization each plug for a specific instance of the speakers, firstly, does not hit production costs in mass production. Secondly, the replacement of the GG in the AU is required only in exceptional cases. This means that the filtering of the AC frequency channels can be approached unconventionally:

1. The frequency of the section LF-MF m HF is taken not lower than 6 kHz, otherwise you will not get a sufficiently uniform amplitude-frequency characteristic (AFC) of the entire speaker in the midrange region, which is very bad, see below. In addition, at a high crossover frequency, the filter is inexpensive and compact;
2. The prototypes for calculating the filter are links and half links of filters of type K, because their phase-frequency characteristics (PFC) are absolutely linear. Without observing this condition, the frequency response in the crossover frequency region will turn out to be significantly uneven and overtones will appear in the sound;
3. To obtain the initial data for the calculation, it is necessary to measure the impedance (impedance) of the LF-MF and HF GG at the crossover frequency. The GG 4 or 8 Ohms indicated in the passport are their active resistance to DC, and the impedance at the crossover frequency will be larger. The impedance is measured quite simply: the GG is connected to an audio frequency generator (GZCH), tuned to the crossover frequency, with an output of at least 10 V to a load of 600 Ohms through a resistor of obviously high resistance, for example. 1 kOhm You can use low-power GZCH and UMZCH high fidelity. The impedance is determined by the ratio of the audio frequency (AF) voltages across the resistor and GG;
4. The impedance of the LF-MF link (GG, heads) is taken as the characteristic impedance ρn of the low-pass filter (LPF), and the impedance of the HF head is taken as ρv of the high-pass filter (HPF). The fact that they are different - well, the fool is with them, the output impedance of the UMZCH, "rocking" the speakers, is negligible compared to this and that;
5. From the side of the UMZCH, reflective-type low-pass and high-pass filters are installed so as not to overload the amplifier and not take power from the associated speaker channel. To GG, on the contrary, they turn to absorbing links, that the return from the filter did not give overtones. Thus, low-pass and high-pass speakers will have at least a link with a half link;
6. The attenuation of the LPF and HPF at the crossover frequency is taken equal to 3 dB (1.41 times), because the steepness of the slopes of K-filters is small and uniform. Not 6 dB, as it may seem, because. filters are calculated by voltage, and the power supplied to the GG depends on it squarely;
7. Adjusting the filter comes down to "muting" a too loud channel. The loudness of the channels at the crossover frequency is measured using a computer microphone, turning off HF and LF-MF in turn. The degree of "muting" is defined as the square root of the ratio of the loudness of the channels;
8. The excessive volume of the channel is removed with a pair of resistors: the quenching one by fractions or units of ohms is connected in series with the GG, and in parallel with both of them - equalizing the greater resistance so that the impedance of the GG with the resistors remains unchanged.

Explanations to the methodology

A technically knowledgeable reader may have a question: does the filter for the complex load work for you? Yes, and in this case - no big deal. The phase response of K-filters is linear, as mentioned, and Hi-Fi UMZCH is almost an ideal voltage source: its output impedance Rout is units and tens of mΩ. Under such conditions, the “reflection” from the HG reactance will partially attenuate in the output absorbing link/filter half link, but for the most part will seep back to the UMZCH exit, where it will disappear without a trace. In fact, nothing will pass into the associated channel, because ρ of its filter is many times greater than Rout. There is one danger here: if the impedance of the GG and ρ are different, then power circulation will begin in the filter output - GG circuit, which will make the bass become dull, “flat”, attacks on the midrange will be prolonged, and the top will be sharp, with a whistle. Therefore, the impedance of the GG and ρ must be adjusted exactly, and in the event of a replacement of the GG, the channel will have to be tuned again.

Note: do not try to filter active speakers with analog active filters on operational amplifiers (op-amps). It is impossible to achieve the linearity of their phase characteristics in a wide frequency range, therefore, for example, analog active filters have not really taken root in telecommunication technology.

What is hifi

Hi-Fi, as you know, is short for High Fidelity - high fidelity (sound reproduction). The concept of Hi-Fi was initially accepted as vague and not subject to standardization, but its informal division into classes gradually developed; the numbers in the list indicate, respectively, the range of reproducible frequencies (operating range), the maximum allowable coefficient of non-linear distortion (THD) at rated power (see below), the minimum allowable dynamic range relative to the room's own noise (dynamics, the ratio of maximum volume to minimum), the maximum allowable uneven frequency response in the midrange and its blockage (decline) at the edges of the operating range:

• Absolute or full - 20-20,000 Hz, 0.03% (-70 dB), 90 dB (31,600 times), 1 dB (1.12 times), 2 dB (1.25 times).
• High or heavy - 31.5-18,000 Hz, 0.1% (-60 dB), 75 dB (5600 times), 2 dB, 3 dB (1.41 times).
• Medium or basic - 40-16,000 Hz, 0.3% (-50 dB), 66 dB (2000 times), 3 dB, 6 dB (2 times).
• Initial - 63-12500 Hz, 1% (-40 dB), 60 dB (1000 times), 6 dB, 12 dB (4 times).

It is curious that high, basic and initial Hi-Fi approximately correspond to the highest, first and second classes of household electroacoustics according to the USSR system. The concept of absolute Hi-Fi arose with the advent of condenser, film-panel (isodynamic and electrostatic), jet and plasma sound emitters. Heavy (Heavy) high Hi-Fi called the Anglo-Saxons, because. High High Fidelity in English is like butter.

What kind of hi-fi do you need?

Home acoustics for modern apartment or houses with good soundproofing must satisfy the conditions for basic Hi-Fi. High there, of course, will not sound worse, but it will cost a lot more. In block Khrushchev or Brezhnevka, no matter how you isolate them, only professional experts distinguish between initial and basic Hi-Fi. The grounds for such a coarsening of the requirements for home acoustics are as follows.

Firstly, the full range of sound frequencies is heard by literally a few people from all over humanity. People gifted with a particularly delicate ear for music, such as Mozart, Tchaikovsky, J. Gershwin, hear high Hi-Fi. Experienced professional musicians in a concert hall confidently perceive basic Hi-Fi, and 98% of ordinary listeners in a sound chamber almost never distinguish between initial and basic in frequency.

Secondly, in the most audible region of the midrange, a person in terms of dynamics distinguishes sounds in the range of 140 dB, counting from the audibility threshold of 0 dB, equal to the intensity of the sound flux of 1 pW per square meter. m, see fig. curves of equal loudness on the right. A sound louder than 140 dB is already pain, and then - damage to the hearing organs and concussion. An expanded symphony orchestra on the most powerful fortissimo produces sound dynamics up to 90 dB, and in the halls of the Grand Opera, Milan, Paris, Vienna Opera Houses and the Metropolitan Opera in New York, it is able to “accelerate” up to 110 dB; such is the dynamic range of leading jazz bands with symphonic accompaniment. This is the limit of perception, louder than which the sound turns into still tolerable, but already meaningless noise.

Note: rock bands can play louder than 140 dB, which Elton John, Freddie Mercury and the Rolling Stones were fond of when they were young. But the dynamics of rock does not exceed 85 dB, because rock musicians cannot play the most delicate pianissimo with all their desire - the equipment does not allow, and there is no rock "in spirit". As for pop music of any kind and movie soundtracks, this is not a topic at all - their dynamic range is already compressed to 66, 60 and even 44 dB during recording, so that you can listen to anything.

Thirdly, natural noises in the quietest living room country house behind the backyards of civilization - 20-26 dB. Sanitary norm noise in the reading room of the library - 32 dB, and the rustle of leaves on fresh wind- 40-45 dB. From this it is clear that the high Hi-Fi speakers of 75 dB are more than enough for meaningful listening in living conditions; the dynamics of modern UMZCH of the average level, as a rule, is not worse than 80 dB. In a city apartment, it is almost impossible to recognize basic and high Hi-Fi by the dynamics.

Note: in a room noisier than 26 dB, the frequency range of your favorite Hi-Fi can be narrowed down to the limit. class, because the effect of masking affects - against the background of indistinct noises, the sensitivity of the ear in frequency decreases.

But in order for Hi-Fi to be high-fi, and not “happiness” for “beloved” neighbors and harm to the health of the owner, it is necessary to ensure even the smallest possible sound distortion, correct reproduction of low frequencies, smooth frequency response in the midrange region, and decide on what is necessary for scoring this room electric power AS. As a rule, there are no problems with HF, because. their SOI "leave" in the inaudible ultrasonic region; you just need to put a good HF head in the speakers. It is enough to note here that if you prefer classics and jazz, it is better to take the HF GG with a cone for a power of 0.2-0.3 from that of the low-frequency channel, for example. 3GDV-1-8 (2GD-36 in the old way) and the like. If you are “rushing” from hard tops, then the HF GG with a dome emitter (see below) with a power of 0.3-0.5 of the power of the low-frequency link will be optimal; drumming with brushes is naturally reproduced only by dome tweeters. However, a good dome tweeter is suitable for any kind of music.

distortion

Sound distortions are possible linear (LI) and non-linear (NI). Linear distortion is, simply, a discrepancy between the average volume level and the listening conditions, for which any UMZCH has a volume control. In expensive 3-way speakers for high Hi-Fi (for example, the Soviet AC-30, aka S-90), power attenuators for midrange and treble are often introduced in order to more accurately adjust the frequency response of the speaker to the acoustics of the room.

As for NI, they, as they say, are innumerable and new ones are constantly being discovered. The presence of NI in the audio path is expressed in the fact that the shape of the output signal (which the sound is already in the air) is not completely identical to the shape of the original signal from the primary source. Most of all they spoil the purity, "transparency" and "juiciness" of the sound of the trace. NI:

1. Harmonic - overtones (harmonics) that are multiples of the fundamental frequency of the reproduced sound. Manifested as excessively roaring bass, sharp and hard midrange and treble;
2. Intermodulation (combination) - the sums and differences of the frequencies of the components of the spectrum of the original signal. Strong combinational NIs are heard as wheezing, and weak, but spoiling the sound, can only be recognized in the laboratory by multi-signal or statistical methods on test phonograms. By ear, the sound seems to be clear, but somehow not so;
3. Transient - "jitter" of the output signal form with sharp rises / falls of the original. They manifest themselves with short wheezing and sobbing, but irregularly, at volume jumps;
4. Resonant (overtones) - ringing, rattling, mumbling;
5. Frontal (distortion of the sound attack) - delaying or, conversely, forcing sharp changes in the overall volume. Almost always occur together with transitional;
6. Noise - hum, rustle, hiss;
7. Irregular (sporadic) - clicks, cods;
8. Interference (AI or IFI, not to be confused with intermodulation). They are characteristic specifically for the AU, in the UMZCH IFI do not occur. Very harmful, because. perfectly audible and unremovable without a major alteration of the speakers. See below for more information on FFI.

Note:"wheezing" and other figurative descriptions of distortion hereinafter are given from the point of view of Hi-Fi, i.e. as already heard by sophisticated listeners. And, for example, speech speakers are designed for SOI at a nominal power of 6% (in China - by 10%) and 1

In addition to interference, speakers can give predominantly NI according to paragraphs. 1, 3, 4 and 5; clicks and cods are possible here as a result of poor-quality workmanship. They fight with transient and frontal NIs in speakers by selecting suitable HGs (see below) and acoustic design for them. Ways to avoid overtones - the rational design of the speaker cabinet and the right choice of material for it, also see below.

It is necessary to linger on harmonic NI in the AC, because they are fundamentally different from those in semiconductor UMZCH and are similar to the harmonic NI tube ULF (low-frequency amplifiers, the old name is UMZCH). A transistor is a quantum device, and its transfer characteristics are not fundamentally expressed by analytical functions. The consequence is that it is impossible to accurately calculate all the harmonics of the transistor UMZCH, and their spectrum stretches to the 15th and higher components. Also, in the spectrum of transistor UMZCH, the proportion of combinational components is large.

The only way to deal with all this mess is to hide the NI deeper under the amplifier's own noise, which, in turn, should be many times lower than the natural noise of the room. I must say that modern circuitry copes with this task quite successfully: according to the current ideas, UMZCH with 1% THD and -66 dB of noise is “no”, and with 0.06% THD and -80 dB of noise is pretty mediocre.

With harmonic NI speaker speakers, the situation is different. Their spectrum, firstly, like that of tube ULFs, is pure - only overtones without a noticeable admixture of combination frequencies. Secondly, the AC harmonics can be traced, just like in lamps, not higher than the 4th. Such an NI spectrum does not noticeably spoil the sound even with a SOI of 0.5-1%, which is confirmed by expert estimates, and the reason for the “dirty” and “sluggish” sound of home-made speakers lies most often in the poor frequency response in the midrange. For your information, if the trumpeter did not properly clean the instrument before the concert and during the game does not splash saliva out of the embouchure in a timely manner, then the THD of, say, a trombone can grow up to 2-3%. And nothing, they play, the audience likes it.

The conclusion from here follows a very important and favorable one: the frequency range and intrinsic harmonics of the NI speakers are not parameters that are critical for the quality of the sound it creates. The sound of speakers with 1% and even 1.5% harmonic NI experts can be attributed to the basic, and even high Hi-Fi, if appropriate. conditions for the dynamics and smoothness of the frequency response.

Interference

IFI is the result of the convergence of sound waves from nearby sources in phase or in antiphase. The result is bursts, up to pain in the ears, or dips of almost zero volume at certain frequencies. At one time, the first-born of the Soviet Hi-Fi 10MAC-1 (not 1M!) Was urgently discontinued after the musicians discovered that this speaker did not reproduce the second octave at all (as far as I remember). At the factory, the prototype was “chased” in a sound meter using the three-signal method, antediluvian even then, and there was no position of an expert with an ear for music in the staff list. One of the paradoxes of developed socialism.

The probability of occurrence of IFI increases sharply with an increase in frequency and, accordingly, a decrease in the wavelength of sound, since for this, the distance between the centers of the emitters must be a multiple of half the wavelength of the reproducible frequency. On MF and HF, the latter changes from units of decimeters to millimeters, therefore, it is impossible to put two or several MF and HF GG in the AU in any way - then IFI cannot be avoided, because. the distances between the HG centers will be of the same order. In general, the golden rule of electroacoustics is one transducer per band, and the brilliant one is one broadband GG for the entire frequency range.

The wavelength of the LF is meters, which is much larger than not only the distance between the GG, but also the size of the speakers. Therefore, manufacturers and experienced amateurs often increase the power of the speakers and improve the bass by pairing or quadrupling (quadruplet) LF GH. However, a beginner should not do this: internal interference of reflected waves “walking” with the speaker itself may occur. To the ear, it manifests itself as resonant NI: it bubbling, gundosing, rattling, why is not clear. So follow the precious rules so as not to sort through the whole speaker over and over again to no avail.

Note: it is impossible to put an odd number of identical GGs in the AS in any case - the FFI is then guaranteed 100%

MF

Novice amateurs pay little attention to the reproduction of medium frequencies - they, they say, any speaker will “sing” - but in vain. MFs are heard best of all, they also account for the original ("correct") harmonics of the basis of everything - basses. The uneven frequency response of the speakers in the midrange is capable of giving combination NI that spoil the sound very much, tk. the spectrum of any phonogram "floats" over the frequency range. Especially - if the speakers use efficient and inexpensive speakers with a short cone stroke, see below. Subjectively, when listening, experts unambiguously prefer speakers with a frequency response to a midrange that smoothly changes over the frequency range within 10 dB over one that has 3 dips or "bumps" of 6 dB each. Therefore, when designing and making speakers, you need to carefully check at every step: will this frequency response not “hunchback” on the midrange?

Note, speaking of bass: rock joke. So, a young promising group broke through to a prestigious festival. In half an hour they will go out, and they are already backstage, worrying, waiting, but the bassist went on a spree somewhere. 10 minutes before the exit - it is not there, 5 minutes - also not. The exit is waving, but the bassist is still missing. What to do? Well, let's play without bass. Absence is an instant collapse of a career forever. They played without bass, it's clear how. They wander to the service exit, spit, swear. Look - a bassist, drunk, with two heifers. They to him - oh you, goat, do you even understand how you threw us?! Where have you been?! - Yes, I decided to listen in the hall. - And what did you hear there? “Dudes, no bass—sucks!”

LF

Bass in music is like the foundation of a house. And in the same way, the "zero cycle" of electroacoustics is the most difficult, complex and responsible. The audibility of sound depends on the energy flux of the sound wave, which depends on the frequency squared. Therefore, the bass is the worst heard, see fig. with curves of equal loudness. To "pump" energy into the bass, you need powerful speakers and UMZCH; in fact, more than half of the power of the amplifier is spent on bass. But at high powers, the probability of the occurrence of NI increases, the strongest and, of course, the audible components of the spectrum of which from the bass will fall just on the best audible mids.

"Pumping" of LFs is further complicated by the fact that the dimensions of the GG and the entire AS are small compared to the wavelengths of LFs. Any source of sound gives it energy the better, the larger its size relative to the wavelength of the sound wave. The acoustic efficiency of the speakers at low frequencies is units and fractions of a percent. Therefore, most of the work and troubles in creating an AU comes down to making it better reproduce low frequencies. But let us remind you once again: do not forget to control the purity of the midrange as often as possible! Actually, the creation of the low-frequency tract of the speaker is reduced to:

• Determination of the required electrical power of LF GG.
• Selecting a LF GH suitable for the given listening conditions.
• The choice of the optimal acoustic design for the selected LF GG (hull design).
• Its correct manufacture in a suitable material.

Power

Sound return in dB (characteristic sensitivity) is indicated in the speaker's passport. It is measured in a sound chamber 1 m from the center of the GG with a measuring microphone located strictly along its axis. The GG is placed on a sound-measuring shield (standard acoustic screen, see the figure on the right) and an electric power of 1 W is supplied (0.1 W for a GG with a power of less than 3 W) at a frequency of 1000 Hz (200 Hz, 5000 Hz). Theoretically, according to these data, the class of the desired Hi-Fi and the parameters of the room / listening area (local acoustics), it is possible to calculate the required electrical power of the GG. But in fact, accounting for local acoustics is so complicated and ambiguous that experts rarely fool around with it.

Note: The GG for measurements is shifted from the center of the screen in order to avoid the interference of sound waves from the front and rear radiating surfaces. The screen material is usually a cake of 5 layers of non-skinned 3-layer pine plywood on casein glue 3 mm thick and 4 gaskets between them made of natural felt 2 mm thick. Everything is glued together with casein or PVA.

It is much easier to go from the existing conditions to the technical sounding of low-noise rooms, corrected for the dynamics and frequency range of Hi-Fi, especially since the results obtained in this case are in better agreement with known empirical data and expert estimates. Then for the initial Hi-Fi it is necessary, with a ceiling height of up to 3.5 m, 0.25 W of the nominal (long-term) electric power of the GG per 1 sq. m floor area, for basic Hi-Fi - 0.4 W/sq. m, and for high - 1.15 W / sq. m.

The next step is to take into account real listening conditions. Hundred-watt speakers capable of operating at microwatt levels are outrageously expensive, on the one hand. On the other hand, if a separate room equipped as a sound-measuring chamber is not allocated for listening, then their “microwhispers” on the quietest pianissimo in any living room will not be heard (see above about natural noise levels). Therefore, we increase the obtained values ​​​​by a factor of two or three in order to “tear off” what is being heard from the noise background. We get for the initial Hi-Fi from 0.5 W / sq. m, base from 0.8 W/sq. m and for high from 2.25 W / sq. m.

Further, since we need high-fi, and not just speech intelligibility, we need to move from nominal power to peak (musical) power. The "juice" of the sound depends primarily on the dynamics of its volume. SOI GG at loudness peaks should not exceed its values ​​for Hi-Fi by a class below the chosen one; for the initial Hi-Fi, we take 3% SOI at the peak. In sales specifications for Hi-Fi speakers, peak power is indicated as more significant. According to the Soviet-Russian methodology, the peak power is 3.33 long-term; according to the methods of Western firms, "music" is equal to 5-8 denominations, but - stop for now!

Note: Chinese, Taiwanese, Indian and Korean methods are ignored. They for basic (!) Hi-Fi at the peak take a telephone THD of 6%. But the Philippines, Indonesia and Australia measure their dynamics correctly.

The fact is that without exception, all Western manufacturers of Hi-Fi GG shamelessly overestimate the peak power of their products. It would be better if they promoted their SOI and the evenness of the frequency response, here they really have something to be proud of. Yes, but an ordinary foreign inhabitant will not understand such difficulties, and if “180W”, “250W”, “320W” are smeared on the speaker, this is really cool. In reality, running the speakers "from there" in the sound meter gives them peaks of 3.2-3.7 ratings. Which is quite understandable, because. this ratio is justified physiologically, i.e. structure of our ears. Conclusion - aiming at Western GGs, go to the company website, look for the rated power there and multiply by 3.33.

Note 9, about the designations of the peak and the nominal value: in Russia, according to the old system, the numbers in front of the letters in the designation of the speaker indicated its rated power, and now they give the peak power. But at the same time, the root with the designation suffix was also changed. Therefore, the same speaker can be designated in completely different ways, see examples below. Look for the truth from reference sources or on Yandex. There, no matter what designation you enter, the results will contain a new one, and the old one next to it in brackets.

In the end, we get for a room up to 12 square meters. m peak for the initial Hi-Fi at 15 W, the base at 30 W and the high at 55 W. These are the smallest allowed values; take GG twice or three times more powerful, it will be better, unless you listen to symphonic classics and very serious jazz. For them, it is desirable to limit the power to 1.2-1.5 of the minimum, otherwise wheezing is possible at the peaks of volume.

You can get by even easier by focusing on proven prototypes. For initial Hi-Fi in a room up to 20 sq. m suitable GG 10GD-36K (10GDSH-1 in the old way), for high - 100GDSH-47-16. They do not need filtering, these are broadband GGs. With basic Hi-Fi it is more difficult, a suitable broadband for it is not found, you need to make a 2-way speaker. Here, at first, the optimal solution is to repeat the electrical part of the old Soviet AS S-30B. These speakers have been working properly and very well for decades in apartments, cafes and just on the street. Shabby utterly, but the sound is kept.

S-30B filtering scheme (without overload indication) is shown in fig. left. Minor revision was made to reduce losses in the coils and the possibility of fitting to various LF GG; if desired, taps from L1 can be made more often, within 1/3 of the total number of turns w, counting from the right end of L1 according to the scheme, the fit will be more accurate. On the right - instructions and formulas for self-calculation and manufacture of filter coils. Precision precision details are not required for this filtering; +/-10% deviations in the inductance of the coils also do not noticeably affect the sound. It is advisable to bring the R2 engine to the back wall for quick adjustment of the frequency response to the room. The circuit is not very sensitive to the impedance of the speakers (unlike the filtering on K-filters), therefore, instead of the indicated ones, other HGs can be used that are suitable in terms of power and resistance. One condition: the highest reproducible frequency (HF) of the LF GH at the level of -20 dB must not be lower than 7 kHz, and the lowest reproducible frequency (LF) of the HF GH at the same level must not be higher than 3 kHz. By shifting-pushing L1 and L2, you can somewhat correct the frequency response in the region of the crossover frequency (5 kHz), without resorting to such complexities as the Zobel filter, which can also increase transient distortion. Capacitors - film with PET or fluoroplastic insulation and sprayed plates (MKP) K78 or K73-16; in extreme cases - K73-11. Resistors - metal film (MOX). Wires - audio from oxygen-free copper with a cross section of 2.5 square meters. mm. Mounting - soldering only. On fig. the right side shows what the original S-30B filtering looks like (with the overload indication circuit), and in fig. below on the left is a 2-way filtering scheme popular abroad without magnetic coupling between the coils (why their polarity is not indicated). On the right there, just in case, is a 3-way filtering of the Soviet AC S-90 (35AC-212).

About wires

Special audio wires are not a product of mass psychosis and not a marketing gimmick. The effect discovered by radio amateurs has now been confirmed by research and recognized by experts: if there is an admixture of oxygen in the copper of the wire, the thinnest, literally in a molecule, oxide film is formed on the metal crystallites, from which the sound signal can be anything but an improvement. In silver, this effect is not found, which is why sophisticated audio gourmets do not skimp on silver wire: merchants shamelessly cheat with copper wires, because. it is possible to distinguish oxygen-free copper from ordinary electrical engineering only in a specially equipped laboratory.

Speakers

The quality of the primary sound emitter (FROM) on the bass determines the sound of the speakers approx. by 2/3; in the midrange and highs - almost completely. In amateur speakers, almost always IZs are electrodynamic GGs (speakers). Isodynamic systems are quite widely used in high-end headphones (for example, TDS-7 and TDS-15, which are readily used by pros to control sound recording), but the creation of powerful isodynamic IS encounters technical difficulties that are still insurmountable. As for the other primary ISs (see the list at the beginning), they are still far from “brought to mind”. This is especially true for prices, reliability, durability and stability of characteristics during operation.

When joining electroacoustics, you need to know how the speakers are arranged and work in acoustic systems, you need the following. The exciter of the speaker is a thin coil of wire oscillating in the annular gap of the magnetic system under the influence of an audio frequency current. The coil is rigidly connected to the sound emitter itself into space - a diffuser (for bass, midrange, sometimes for high frequencies) or a thin, very light and rigid dome diaphragm (for high frequencies, rarely - for midrange). The efficiency of sound emission strongly depends on the diameter of the IZ; more precisely, it depends on its relation to the wavelength of the emitted frequency, but at the same time, with an increase in the diameter of the IZ, the probability of occurrence of non-linear distortions (NI) of the sound due to the elasticity of the IZ material also increases; more precisely - not its infinite rigidity. They fight against NI in IZ by making radiating surfaces from sound-absorbing (anti-acoustic) materials.

The diameter of the cone is larger than the diameter of the coil, and in diffuser GGs, it and the coil are attached to the speaker housing with separate flexible suspensions. The diffuser configuration is a thin-walled hollow cone with its apex facing the coil. The suspension of the coil simultaneously holds the top of the diffuser, i.e. its suspension is double. The generatrix of a cone can be rectilinear, parabolic, exponential and hyperbolic. The steeper the cone of the diffuser converges to the top, the higher the return and the lower the NI dynamics, but at the same time its frequency range narrows and the radiation directivity increases (the radiation pattern narrows). The narrowing of the DN also narrows the area of ​​the stereo effect and moves it away from the frontal plane of the speaker pair. The diameter of the diaphragm is equal to the diameter of the coil and there is no separate suspension for it. This drastically reduces the SOI GG, because. the diffuser suspension is a very noticeable source of NI sound, and the material for the diaphragm can be taken very hard. However, the diaphragm is capable of emitting sound well only at sufficiently high frequencies.

The coil and the diffuser or diaphragm, together with the suspensions, make up the mobile system (PS) of the GG. The PS has a frequency of its own mechanical resonance Fp, at which the mobility of the PS increases sharply, and a quality factor Q. If Q> 1, then the speaker without a properly selected and executed acoustic design (see below) will wheeze at Fp at a power less than the nominal one, not that peak, this is the so-called. blocking GG. Locking does not apply to distortions, because is a design and manufacturing defect. If 0.7

The efficiency of transferring the energy of an electrical signal to sound waves in air is determined by the instantaneous acceleration of the diffuser / diaphragm (who is familiar with mathematical analysis - the second derivative of its displacement with respect to time), since air is highly compressible and highly fluid. The instantaneous acceleration of the coil pushing/pulling the diffuser/diaphragm must be somewhat greater, otherwise it will not "shake" the OUT. A few, but not much. Otherwise, the coil will bend and cause the emitter to vibrate, which will lead to the appearance of NI. This is the so-called membrane effect, in which longitudinal elastic waves propagate in the diffuser/diaphragm material. Simply put, the diffuser / diaphragm should “slow down” the coil a little. And here again there is a contradiction - the stronger the emitter “slows down”, the stronger it radiates. In practice, the "braking" of the emitter is done in such a way that its NI in the entire range of frequencies and powers fit into the norm for a given Hi-Fi class.

Note, output: do not try to "squeeze" out of the speakers what they cannot. For example, speakers on 10GDSh-1 can be built with a frequency response unevenness at the midrange of 2 dB, but in terms of SOI and dynamics, it still pulls on Hi-Fi no higher than the initial one.

At frequencies up to Fp, the membrane effect never manifests itself, this is the so-called. piston mode of operation of the GG - the diffuser / diaphragm just go back and forth. Higher in frequency, the heavy diffuser is no longer able to keep up with the coil, the membrane radiation starts and gets stronger. At a certain frequency, the speaker begins to radiate only as a flexible membrane: at the junction with the suspension, its diffuser is already motionless. At 0.7

The membrane effect dramatically improves the return of GG, tk. the instantaneous accelerations of the vibrating sections of the IZ surface turn out to be very large. This circumstance is widely used by designers of HF and partially MF GG, the distortion spectrum of which immediately goes into ultrasound, as well as when designing GG not for Hi-Fi. SOI GG with a membrane effect and the evenness of the frequency response of speakers with them strongly depend on the mode of the membrane. In the zero mode, when the entire surface of the FM trembles as if in time with itself, Hi-Fi up to the middle inclusive can be achieved at low frequencies, see below.

Note: the frequency at which the HG switches from the “piston to the membrane”, as well as the change in the membrane mode (not growth, it is always integer) depend significantly on the diffuser diameter. The larger it is, the lower in frequency and stronger the speaker begins to “membrane”.

Woofers

High-quality piston woofers GG (simply - “piston”; in English woofers, barking) are made with a relatively small, thick, heavy and hard anti-acoustic diffuser on a very soft latex suspension, see pos. 1 in fig. Then Fr is below 40 Hz or even below 30-20 Hz, and Q<0,7. В мембранном режиме поршневые ГГ способны работать до частот 7-8 кГц на нулевой-первой модах.

The periods of low-frequency waves are long, all this time the diffuser in the piston mode must move with acceleration, and therefore the diffuser stroke becomes long. Low frequencies without acoustic design are not reproduced, but it is always closed to one degree or another, isolated from free space. Therefore, the diffuser has to work with a large mass of so-called. of the attached air, for the “buildup” of which a significant effort is required (which is why piston GGs are sometimes called compression), as well as for the accelerated movement of a heavy diffuser with a low quality factor. For these reasons, the magnetic system of the piston GG has to be made very powerful.

Despite all the tricks, the return of the piston GG is small, because. it is impossible for a low-frequency diffuser to develop a large acceleration at long wavelengths: the elasticity of the air is not enough to accept the energy given off. It will spread to the sides, and the speaker will go into locking. In order to increase the return and smoothness of the motion of the moving system (to reduce SOI at high power levels), designers go all out - they use differential magnetic systems, with half-scattering, and other exotics. THD is further reduced by filling the magnetic gap with a non-drying rheological fluid. As a result, the best modern pistons reach a dynamic range of 92-95 dB, and the THD at nominal power does not exceed 0.25%, and at peak power - 1%. All this is very good, but the prices - mom, don't worry! $1000 for a pair with differential magnets and refilling for home acoustics, matched in terms of output, resonant frequency and flexibility of the moving system, is not the limit.

Note: LF GG with rheological filling of the magnetic gap are suitable only for LF links of 3-way speakers, because completely incapable of working in the membrane mode.

Piston GGs have another serious flaw: without strong acoustic damping, they can mechanically collapse. Again, simply: behind the piston speaker there should be a kind of air cushion loosely connected to the free space. Otherwise, the diffuser at the peak will break off the suspension and it will fly out along with the coil. Therefore, you can not put the "piston" in any acoustic design, see below. In addition, piston GGs do not tolerate forced braking of the PS: the coil burns out immediately. But this is already a rare case, the speaker cones are usually not held by hand and matches are not inserted into the magnetic gap.

Craftsmen take note

A “folk” way to increase the return of piston GGs is known: an additional annular magnet is firmly attached to the standard magnetic system from the rear, without altering anything in dynamics, with the repelling side. It is repulsive, otherwise, when a signal is applied, the coil will immediately be torn off from the diffuser. In principle, it is possible to rewind the speaker, but it is very difficult. And nowhere else has a rewinding speaker become better or at least remain the same as it was.

But it's not really about that. Enthusiasts of this refinement claim that the field of an external magnet concentrates the field of a regular magnet near the coil, which increases the acceleration of the PS and recoil. This is true, but Hi-Fi GG is a very finely balanced system. Recoil is actually a little higher. But here the SOI at its peak immediately "jumps" so that sound distortions become well audible even to inexperienced listeners. At nominal, the sound can become even cleaner, but without Hi-Fi speakers it’s already high-fi.

Leading

So in English (managers) are called SC GG, because. it is the midrange that accounts for the vast majority of the semantic load of the musical opus. The requirements for the midrange GG for Hi-Fi are much softer, so most of them are made of a traditional design with a large cone, cast from cellulose mass along with the suspension, pos. 2. Reviews about the midrange of the dome and with metal diffusers are contradictory. The tone prevails, they say, the sound is harsh. Fans of the classics complain that the bowed speakers squeal from the "non-paper" speakers. Almost everyone recognizes the sound of the midrange GG with plastic diffusers as dull and at the same time hard.

The course of the diffuser of the midrange GG is made short, because. its diameter is comparable to the wavelengths of the MF and the transfer of energy into the air is not difficult. To increase the attenuation of elastic waves in the diffuser and, accordingly, reduce NI, along with expanding the dynamic range, finely chopped silk fibers are added to the mass for casting the Hi-Fi cone midrange GG, then the speaker operates in a piston mode in almost the entire midrange range. As a result of the application of these measures, the dynamics of modern midrange GG of the average price level turns out to be no worse than 70 dB, and THD at a nominal value of no more than 1.5%, which is quite enough for high Hi-Fi in a city apartment.

Note: silk is added to the material of the cone of almost all good speakers, this is a universal way to reduce THD.

Tweeters

In our opinion - squeakers. As you may have guessed, these are tweeters, HF YY. Spelled with a single t, it's not a gossip social media name. It would be generally easy to make a good “tweeter” from modern materials (the NI spectrum immediately goes into ultrasound), if not for one circumstance - the diameter of the emitter in almost the entire HF range turns out to be of the same order or less than the wavelength. Because of this, interference is possible on the emitter itself due to the propagation of elastic waves in it. In order not to give them a “hook” for radiation into the air at random, the diffuser / dome of the HF GG should be as smooth as possible, for this purpose the domes are made of metallized plastic (it absorbs elastic waves better), and the metal domes are polished.

The criterion for choosing the HF GG is indicated above: dome ones are universal, and for fans of the classics who require necessarily “singing” soft tops, diffuser ones are more suitable. It is better to take these elliptical ones and put them in the speakers, orienting their long axis vertically. Then the dynamics of the dynamics in the horizontal plane will be wider, and the stereo zone will be larger. Still on sale there is a HF GG with a built-in horn. Their power can be taken as 0.15-0.2 of the power of the low-frequency link. As for technical quality indicators, any HF GG is suitable for Hi-Fi of any level, as long as it is suitable in terms of power.

Widths

This is a colloquial nickname for broadband GGs (GGSh) that do not require defiltering of AC frequency channels. The emitter of a simple GGSh with a common excitation consists of an LF-MF diffuser and a HF cone rigidly connected to it, pos. 3. This is the so-called. a coaxial radiator, which is why the GGSh is also called coaxial speakers or simply coaxes.

The idea of ​​​​the GGSh is to give the membrane mode to the HF cone, where it does not particularly harm, and let the cone at the bass and at the bottom of the midrange work “on the piston”, for which the low-midrange cone is corrugated across. This is how broadband GGs are made for initial, sometimes average Hi-Fi, for example. mentioned 10GD-36K (10GDSH-1).

The first HF cone GGS went on sale in the early 50s, but they never achieved a dominant position in the market. The reason is the tendency to transient distortion and the delay in the attack of the sound because the cone dangles and sloshes from the shocks of the cone. Listening to Miguel Ramos playing the Hammond electric organ through a coax with a cone is unbearably painful.

Coaxial GGSh with separate excitation of LF-MF and HF emitters, pos. 4, this shortcoming is devoid of. In them, the RF link is driven by a separate coil from its own magnetic system. The sleeve of the HF coil passes through the LF-MF coil. PS and magnetic systems are located coaxially, i.e. along one axis.

GGSh with separate excitation at low frequencies in all technical parameters and subjective sound assessments are not inferior to piston GGs. On modern coaxial speakers, you can build very compact speakers. The disadvantage is the price. A coaxial for high Hi-Fi is usually more expensive than a LF-MF + HF set, although it is cheaper than LF, MF and HF for a 3-way speaker.

Auto

Car speakers formally also belong to coaxial speakers, but in reality they are 2-3 separate speakers in one case. HF (sometimes midrange) GG are suspended in front of the diffuser LF GG on the bracket, see on the right in fig. at first. Filtering is always built-in, i.e. There are only 2 terminals on the case for connecting wires.

The task of auto speakers is specific: first of all, to “shout out” the noise in the car, so their designers don’t really struggle with the membrane effect. But for the same reason, auto-speakers need a wide dynamic range, at least 70 dB, and their cones are necessarily made with silk or use other measures to suppress higher membrane modes - the speaker should not wheeze even in a car on the move.

As a result, auto speakers are in principle suitable for Hi-Fi up to medium inclusive, if you choose the right acoustic design for them. In all the speakers described below, you can put auto-speakers of a suitable size and power, then you will not need a cutout for the HF GG and filtering. One condition: the standard terminals with clamps must be very carefully removed and replaced with lamellas for wiring. Speakers made from modern car speakers allow you to listen to good jazz, rock, even individual pieces of symphonic music and many chamber music. Of course, they won't pull Mozart's violin quartets, but very few people listen to such dynamic and meaningful opuses. A pair of auto speakers will cost several times, up to 5 times, cheaper than 2 sets of GG with filter components for a 2-way speaker.

frisky

Friskers, from frisky, this is how American radio amateurs called small-sized low-power GGs with a very thin and light diffuser, firstly, for their high output - a pair of “frisky” 2-3 W each sounds a room of 20 square meters. m. Secondly - for the hard sound: "frisky" work only in the membrane mode.

Manufacturers and sellers do not single out “frisky” in a special class, because. they are, in theory, not Hi-Fi. The speaker is like a speaker in any Chinese radio or cheap computer speakers like that. However, on the "frisky" one can make good speakers for the computer, providing Hi-Fi up to and including the average in the vicinity of the desktop.

The fact is that the "frisky" ones are able to reproduce the entire sound range, you only need to reduce their SOI and smooth out the frequency response. The first is achieved by adding silk to the diffuser, here you need to navigate by the manufacturer and his (not trade!) Specifications. For example, all GGs of the Canadian company Edifier with silk. By the way, Edifier is a French word and is read "edifier" and not "idifier" in the English manner.

The frequency response of the "frisky" is leveled in two ways. Small bursts / dips are already removed by silk, and larger bumps and troughs are eliminated by acoustic design with free exit to the atmosphere and a damping pre-chamber, see fig.; see an example of such an AS below.

Acoustics

Why do you need acoustic design at all? At low frequencies, the dimensions of the sound emitter are very small compared to the length of the sound wave. If you just put the speaker on the table, the waves from the front and rear surfaces of the diffuser will immediately converge in antiphase, cancel each other out, and you won’t hear bass at all. This is called an acoustic short circuit. You can’t just muffle the speaker from the rear to the bass: the diffuser will have to strongly compress a small volume of air, which is why the resonance frequency of the PS will “jump” so high that the speaker simply cannot reproduce the bass. From here follows the main task of any acoustic design: either to extinguish the radiation from the rear side of the GG, or to turn it over by 180 degrees and re-emit it in phase from the front of the speaker, while at the same time preventing the expenditure of energy of the diffuser movement on thermodynamics, i.e. on compression-expansion of air in the AC case. An additional task is, if possible, to form a spherical sound wave at the output of the speaker, because in this case, the stereo effect zone is the widest and deepest, and the effect of room acoustics on the sound of the speakers is the least.

Note, an important corollary: for each speaker cabinet of a specific volume with a specific acoustic design, there is an optimal excitation power range. If the output power is low, it will not swing the acoustics, the sound will be dull, distorted, especially at low frequencies. An excessively powerful GG will go into thermodynamics, which will cause blocking.

The purpose of the speaker cabinet with acoustic design is to provide the best reproduction of low frequencies. Durability, stability, appearance - by itself. Acoustically, home speakers are designed in the form of a shield (speakers built into furniture and building structures), an open box, an open box with an acoustic impedance panel (PAS), a closed box of normal or reduced volume (small speakers, MAC), a phase inverter (FI), passive radiator (PI), direct and reverse horns, quarter-wave (HF) and half-wave (HF) labyrinths.

Built-in acoustics is a subject of special discussion. Open boxes from the era of tube radios, it is unrealistic to get an acceptable stereo from them in an apartment. Of the others, it is best for a beginner for his first AS to opt for a PV labyrinth:

• Unlike others, except FI and PI, PV labyrinth allows you to improve bass at frequencies below the natural resonant frequency of the woofer.
• Compared to the FI PV, the labyrinth is structurally and easy to set up.
• Compared to PI PV, the labyrinth does not require expensive purchased additional components.
• The cranked PV labyrinth (see below) creates a sufficient acoustic load for the GG, while at the same time having a free connection with the atmosphere, which makes it possible to use low-frequency GG with both long and short diffuser strokes. Up to replacement in already built speakers. Of course, only a couple. The radiated wave in this case will be practically spherical.
• Unlike all, except for the closed box and the HF labyrinth, the acoustic column with the PV labyrinth is able to smooth out the frequency response of the LF GG.
• Speakers with a PV labyrinth are structurally easily pulled into a tall thin column, which facilitates their placement in small rooms.

As for the penultimate point - are you surprised if experienced? Consider this one of the promised revelations. And see below.

PV maze

Labyrinths are often considered acoustic design such as a deep slot (Deep Slot, a type of HF labyrinth), pos. 1 in Fig., and convolutional reverse horn (pos. 2). We will touch on the horns, but as for the deep slot, this is actually a PAS, an acoustic shutter that provides free communication with the atmosphere, but does not let sound out: the depth of the slot is a quarter of the wavelength of its tuning frequency. It is easy to verify this by measuring the sound levels in front of the front of the speaker and in the opening of the slot using a highly directional microphone. Resonance at multiple frequencies is suppressed by lining the gap with a sound absorber. A deep slot speaker also dampens any speakers, but raises their resonant frequency, albeit less than a closed box.

The initial element of the PV labyrinth is an open half-wave pipe, pos. 3. As an acoustic design, it is unsuitable: while the wave from the rear reaches the front, its phase will be reversed by another 180 degrees, and the same acoustic short circuit will turn out. On the frequency response of the PV, the pipe gives a high sharp peak, causing the GG to lock at the tuning frequency Fn. But what is already important - Fn and the natural resonance frequency of the GG f (which is higher - Fp) are theoretically not related to each other, i.e. bass can be expected to improve below f (Fp).

The easiest way to turn a pipe into a maze is to bend it in half, pos. 4. This will not only phase the front with the rear, but also smooth out the resonant peak, because the paths of the waves in the pipe will now be different in length. In this way, in principle, it is possible to smooth the frequency response to any predetermined degree of evenness by increasing the number of knees (it should be odd), but in reality it is very rare to use more than 3 knees - the damping of the wave in the pipe interferes.

In the chamber PV labyrinth (pos. 5), the knees are divided into the so-called. Helmholtz resonators - cavity tapering towards the rear end. This further improves the damping of the HG, smoothes the frequency response, reduces losses in the labyrinth and increases the radiation efficiency, because. the rear exit window (port) of the labyrinth always works with "backwater" from the last chamber. Having partitioned the chambers on intermediate resonators, pos. 6, it is possible to achieve a frequency response with a diffuser GG that almost satisfies the requirements of absolute Hi-Fi, but setting up each of a pair of such speakers requires somewhere from six months (!) of the work of an experienced specialist. Once upon a time, in a certain narrow circle, the labyrinth-chamber speaker with the separation of the chambers was called Cremona, with a hint of the unique violins of Italian masters.

In fact, to obtain a frequency response for high Hi-Fi, it turns out that just a pair of cameras on the knee is enough. Drawings of speakers of this design are given in Fig; on the left - Russian development, on the right - Spanish. Both are very good outdoor acoustics. “For complete happiness”, it would not hurt the Russian woman to borrow the Spanish stiffness ties that support the partition (beech sticks with a diameter of 10 mm), and in return to give a smoothing of the pipe bend.

In both of these speakers, one more useful property of the chamber labyrinth is manifested: its acoustic length is greater than the geometric one, because the sound lingers somewhat in each chamber before passing on. Geometrically, these labyrinths are tuned to somewhere around 85 Hz, but measurements show 63 Hz. In reality, the lower limit of the frequency range is 37-45 Hz, depending on the type of LF GG. When the S-30B's filtered speakers are rearranged into such enclosures, the sound changes amazingly. For the better.

The excitation power range for these speakers is 20-80 W peak. Sound-absorbing lining here and there - synthetic winterizer 5-10 mm. Tuning is not always necessary and easy: if the bass is deaf, the port is covered symmetrically on both sides with pieces of foam until the optimal sound is obtained. This should be done slowly, each time listening to the same segment of the phonogram for 10-15 minutes. It must have strong mids with a sharp attack (mids control!), For example, a violin.

jet flow

The chamber labyrinth is successfully combined with the usual tortuous one. An example is the desktop acoustic system Jet Flow (jet stream) developed by American radio amateurs, which made a splash in the 70s, see fig. on right. Case width on the inside - 150-250 mm for speakers 120-220 mm, incl. "frisky" and autodynamics. Body material - pine, spruce, MDF. Sound-absorbing lining and adjustment are not required. Excitation power range - 5-30 W peak.

Note: there is confusion with Jet Flow now - jet sound emitters are sold under the same brand.

For high-spirited and computer

It is also possible to smooth out the frequency response of auto-speakers and “frisky” ones in an ordinary convoluted labyrinth by arranging a compression damping (not resonating!) prechamber in front of its entrance, indicated by K in fig. below.

This mini speaker is designed for PC instead of the old cheap one. The speakers used are the same, but how they start to sound is simply amazing. If the diffuser is with silk, otherwise it makes no sense to fence the garden. An additional advantage is a cylindrical body, on which the midrange interference is close to the minimum, it is less only on a spherical body. Working position - with an inclination forward-up (AC - sound projector). Excitation power - 0.6-3 W nominal. Assembly is carried out in the following. order (glue - PVA):

• For children 9 glue a dust filter (you can use scraps of nylon tights);
• Det. 8 and 9 are pasted over with synthetic winterizer (indicated in yellow in the figure);
• Assemble a package of partitions on the screed and spacers;
• Glue the padding rings marked in green;
• The package is wrapped, gluing, with whatman paper to a wall thickness of 8 mm;
• The body is cut to size and the prechamber is pasted over (highlighted in red);
• Paste children. 3;
• After complete drying, they sand, paint, attach a stand, mount the speaker. Wires to it pass along the bends of the labyrinth.

About horns

Horn speakers have a high return (remember why he just does it, a mouthpiece). The old 10GDSH-1 yells through a horn so that the ears wither, and the neighbors “I can’t be happy at all”, which is why many are addicted to horns. In home speakers, convoluted horns are used as less bulky. The reverse horn is excited by the rear radiation of the GG and is similar to the PV labyrinth in that it rotates the phase of the wave by 180 degrees. But otherwise:

1. Structurally and technologically much more complicated, see fig. below.
2. It does not improve, but on the contrary, spoils the frequency response of the speakers, because The frequency response of any horn is uneven and the horn is not a resonating system, i.e. it is impossible to correct its frequency response in principle.
3. The radiation from the horn port is significantly directed, and its wave is rather flat than spherical, so a good stereo effect cannot be expected.
4. It does not create a significant acoustic load of the GG and at the same time requires significant power for excitation (we also remember whether they whisper into a speakerphone). The dynamic range of horn speakers can be extended at best to basic Hi-Fi, and for piston speakers with a very soft suspension (and therefore good and expensive), the cone breaks out very often when the GG is installed in the horn.
5. Gives overtones more than any other type of acoustic design.

Frame

The speaker cabinet is best assembled on beech dowels and PVA glue, its film retains its damping properties for many years. For assembly, one of the sidewalls is placed on the floor, the bottom, lid, front and rear walls, partitions are placed, see fig. on the right, and cover with the other sidewall. If the outer surfaces are to be finished, steel fasteners can be used, but always with gluing and sealing (plasticine, silicone) of non-glue seams.

Much more important for sound quality is the choice of body material. The ideal option is a musical spruce without knots (they are a source of overtones), but it is unrealistic to find its large boards for speakers, because Christmas trees are very knotty trees. As for the plastic cases of the speakers, they sound good only in industrial production, solid-cast, and amateur home-made products made of transparent polycarbonate, etc., are a means of self-expression, not acoustics. They will tell you that this sounds good - ask to turn it on, listen and believe your ears.

In general, it is difficult with natural wood materials for speakers: completely straight-grained pine without defects is expensive, and other available building and furniture species give overtones. It is best to use MDF. The Edifier mentioned above has long since completely switched to it. The suitability of any other tree for AS can be determined as follows. way:

1. The test is carried out in a quiet room, in which you yourself must first stay in silence for half an hour;
2. Piece of board approx. 0.5 m is placed on prisms from segments of a steel corner, laid at a distance of 40-45 cm from each other;
3. The knuckle of a bent finger knocks approx. 10 cm from any of the prisms;
4. Repeat tapping exactly in the center of the board.

If in both cases the slightest ringing is not heard, the material is suitable. The better, the softer, duller and shorter the sound. According to the results of such a test, you can make good speakers even from chipboard or laminate, see the video below.

Good afternoon lovers of good sound! Today I will introduce you to Fedor Gartsuev and his very interesting Suono project. An interesting step-by-step production of acoustics with your own hands, as a result, very high-class acoustic systems turned out!

The idea to create something unusual that no one else would have, my brother and I had a long time ago. The love for true music left no doubts that it would be acoustic systems made by one's own hands. While studying at the university, there were even trial versions in the form of two-way "pillars" based on speakers from and a Chinese "tweeter". Then invaluable experience was gained in working with wood, there was also an understanding of what could be done and what would have to be tinkered with, it became necessary to purchase a tool. We are well aware of the importance of careful calculation of all parameters of acoustics and sound settings. At that moment, we could not afford any of this, so the implementation of the plan was postponed indefinitely ...

And last summer, free time appeared, we decided to realize our plans, to make acoustics with our own hands. We started working on the project. I didn’t want to make standard parallelepipeds, there was an idea to “tear” some eminent brand. I really liked Sonus Faber Stradivari, Aida, Jamo Epicon 8, but in each one something did not suit me, then my brother (later, they nevertheless found very interesting solutions). We went through a lot of options (see the picture), and in the end we came up with a project that suited both of them (later it was corrected for the speakers we bought).

After reading the literature and thematic sites, analyzing the design of Hi-End class acoustics, as well as being guided by logic, they also came to the conclusion by their own intuition: the design of the cabinets must meet the following requirements:

1. Prevent standing waves inside the column.

2. Do not create sound distortion caused by resonances and re-reflection of sound waves in acoustics.

To ensure the first condition, the back panel was made narrow, the lack of parallel surfaces also contributes to this, and at the same time creates the effect of "endless space". But the column needs volume, so the front panel turned out to be quite wide. Most companies try to make the speaker as narrow as possible, but acoustics with a wide front panel sound more.

To ensure the second condition, the panel was broken at angles of 7.5 and 15 degrees to the radiation plane
speakers. Concave side surfaces, not a single plane perpendicular to each other or to the wave propagation front, all this serves the same purpose - achieving, if not Hi-End, then at least good Hi-Fi. Two phase inverters are installed at the back, however, they do not serve to resonantly amplify low frequencies, but to equalize the pressure inside the column and are tuned to other frequencies so that they do not “whistle” when air passes through - they put two on each column. The cabinet is mounted on four copper spikes, and the stand itself stands on three steel supports with plastic lining, with the ability to adjust the height and angle of inclination, all this is done so that the vibration of the speakers is not transmitted to the supporting surface. Seen from above, AC reminiscent of a Soviet mouthpiece. Bulkheads are installed inside for rigidity and to give the side surfaces the desired bending radius. The edges of the front and back panels are rounded. It was also planned to glue the sides with veneer for aesthetics.

Work began with the selection of speakers. Break a bunch of sites, settled on Polish speakers Alphard. We found their representative office in Minsk, from which everything necessary was purchased, in addition, it turned out that the company was engaged in the manufacture of professional speakers and could provide assistance in the project. Looking ahead, I’ll say that we entrusted them with the calculation and manufacture of crossovers, as well as the final fine-tuning of the sound, which saved a lot of time and money. And themselves on the hulls.

Two sheets of plywood 18 mm thick and 9 meters of timber 95 × 35 mm were purchased. Plywood was lined, cut into the necessary parts. Straight lines were cut with a circular saw according to the rule, and curved lines - with a milling cutter (in passing, a compass was made for the milling cutter with the ability to set the radius from 300 to 1500 mm). I’ll make a reservation right away: cutting 18 mm plywood with a milling cutter is a bad idea, it’s better to cut the workpiece with an electric jigsaw with an indent of 2-3 mm and bring the shape with a cutter, the surface will be cleaner. Complex details were printed on whatman paper at a scale of 1:1 and made something like templates. For manufacturing details took about a month, unfortunately, this process was not photographed. After processing all the details, they assembled:

They assembled everything with the help of corners, self-tapping screws and carpentry glue.

In the photo above, holes for speakers, phase inverters and acoustic terminals have already been cut. To dampen any possible resonances and overtones, it was decided to lay out the inner surfaces with batting: they cut it with a knife on paper, fixed it with a stapler. Immediately, in the lower cavity, they installed.

After long mockery of plywood 18 mm thick, it was not possible to bend it with the desired radius. Therefore, it was decided to build the thickness of the side panels from three layers of plywood thinner. Each layer was screwed to the spacers with self-tapping screws and smeared with wood glue to glue them together. The joints of all panels were lubricated with sealant from the inside. The gap between the panels in the photo is not crappy build quality. The screws had to be loosened, otherwise the side panels would not fit. The top caps are rolled by the bypass cutter straight over the column.

Final fitting and assembly of some elements:

After the main part of the hulls was assembled, we started grinding, puttying, grinding again ... and so on until smooth, even surfaces were obtained. It took us two jars of putty and a set of grinding wheels. There was a lot of dust.

After everything was sanded, we started pasting the speakers with veneer. The main color of the speakers is black gloss, contrasting veneer patterns were intended to dilute this “blackness” and give a more aesthetic look. An experienced eye will immediately recognize the Jamo Epicon 8. The veneer was cut according to patterns from whatman paper, with a knife on paper. If the veneer is thick (we had a thickness of 0.6 mm), then you don’t need to try to cut it off immediately to the full depth - it’s big that it will burst.

This is not described in the instructions for the glue that was bought along with the veneer, but from my experience I will say: it is better to apply the glue on the surface, and not on the veneer, and let it stand for about three minutes. It is better to protect the surfaces around the pasting area with masking tape - the glue “warps” the plywood - these places will then have to be sanded, and the paint does not want to stick in these places at all.

While the glue dries, it is advisable to periodically roll the veneer with a roller, as it gets wet from the glue, air cavities form under it, if they are not immediately removed, then it will be very problematic to remove them.

After the glue has dried, the veneer can be sanded. Left before sanding, right after. It doesn’t look very beautiful right away, but after applying varnish or stain, everything changes.

For lack of another room, they painted on the balcony. Before painting, the balcony was thoroughly washed and hung with cellophane to prevent dust from entering the painting area. The cases were “vacuumed” and wiped with a lint-free cloth (sold in car dealerships). It is not necessary to wipe with a damp cloth - the veneer is very afraid of liquids, it begins to delaminate. To prevent paint from getting on the veneer, it was covered with masking tape. Since the surfaces are large, it is better to stick the tape only along the edges, and fill sheets of paper cut out in shape under it.

Acrylic was chosen as the paint, applied.

The first layer will reveal all the imperfections of the wood (scratches, dimples, gaps) that were made during sanding. Everything that has appeared is cleaned, puttied, polished.

After that, several more layers of paint are applied. After the paint dries, the masking tape is removed, which was probably the most pleasant moment in all four months. There was an idea to cover the veneer with mahogany wood stain, but it looked gloomy on the test board, so we decided to leave it as it is.

We paint the strips (we left gaps between the strips of veneer 2 mm), limiting them with masking tape:

Let's name it. To do this, we come up with a beautiful word or phrase, we borrowed the name from the Italian language. We put the name on a special film, using plotter cutting, such a service is available everywhere and is inexpensive. We glue the film (it is self-adhesive) on the surface and apply paint, we used the car in a can.

After the paint has dried, remove the film and get a beautiful inscription:

We glue a plate with the characteristics of the speakers on the back panel; we screw the bottom stand and footrests, nothing complicated here, simple mechanical assembly. We cover everything with varnish from the same spray gun. The veneer acquired a yellowish tint, gloss appeared on the paint.

We clog the phase inverters, it is necessary to beat more carefully, we still broke one, we had to buy more b. We solder the acoustic terminals, put them on the sealant and screw them on.

Solder and install speakers. It is worth noting that on the inside of the speakers along the edge, we glued rubber tubes to prevent air from “walking” through possible gaps.

This is the final step. We put the speakers on the floor; check the impedance with a multimeter, connect the amplifier ...

First audition. It was the most long-awaited and exciting event - the result of four months of work. I won't say that the sound has reached the High-End level (although I don't even know how it should sound), but it didn't disappoint either.

Compared with existing Sony SS-F6000. At first, the sound seemed (the ears got used to a different sound), but after a week of listening, it began to seem the only right one. The sound is more "adult" compared to the "disco-pop" sound of Sony. The bass is not as powerful, but more collected, without boominess. Each tool is in its place, has its own weight, is clearly distinguishable, does not stick out and does not hide. Even at maximum volume, the music does not merge into one continuous roar. I can’t say anything about it: there is nowhere and nothing to measure the characteristics.

Speakers Alphard WH656, Alphard WH506, Alphard TW-317, woofer, mid and tweeter, respectively.

Few numbers:

1. The speakers cost $400, of which $270 went to speakers and crossovers.
2. Maximum power 300W.
3. Impedance 4 ohm.
4. The total weight of one column is 38 kg.

Dimensions 1135×370×315mm

On my own behalf and on behalf of numerous fans of the Zvukomania website, I would like to express and wish great creative success to Fedor Gartsuev!

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Do not be afraid to remake the equipment, look for your own !!!

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The quality of sound reproduction in a car depends entirely on the location of the device in the passenger compartment. It is also necessary to take into account all the technical parameters and the resonance indicator of the “boxes”. The housing of the audio playback device to be used in a particular application is ideally made of suitable materials capable of providing the necessary resonance. It is for this reason that the most productive work is do-it-yourself work. But how to make columns if you have never done this before? To fully understand the matter and find an answer to this question, it is necessary to understand all the nuances of creating acoustic devices. Today you will get acquainted with information that will help you create a case yourself, which will positively affect the budget and give you a lot of useful experience.

What is important for speakers?

To begin with, it is worth deciding on the size of the equipment. And to determine the size, you should choose a location:

• The most popular place is the trunk, because there is enough space. Also in this compartment there are all conditions for creating a certain resonance, which makes the sound a little different.
• You can also mount near the rear windows, but then you will have to reduce the size of the cases, since large devices simply will not fit.

How to make speakers with your own hands at home? To do this, you need to become more familiar with the four stages of creation.

measurements

To determine the dimensions of the case, you need:

• Choose a place.
• Estimate the space occupied.
• Measure the allotted area.

Important! If the trunk is chosen as the location, then 30 centimeters is quite enough, and for location in the rear seats - at least 15 centimeters.

What are we building from?

In order to assemble columns, you should choose the following materials:

• Chipboard. It will be very easy to find such material, and the democratic price tag contributes. The main advantage of chipboard is a good return, which will save the motorist from listening to distortions. Also, the weight of the chipboard structure will be practically not noticeable.
• Ebonite. Hard rubbers look good, but the muffled sound is a bit frustrating. In addition, it will be very difficult for you to find a piece in the shape of a rectangle.

Important! Also, some buyers complain about an unpleasant smell, but ebonite is more flame resistant, unlike chipboard, so short circuits (short circuits) are not terrible for him.

• Wood. You can use any wood as a body, but seasoned experts recommend giving preference to oak or pine, since their structure has a good effect on the sound. In addition, no one forgets about the appearance, which in this case can be made very attractive.

Important! Wooden structures can be covered with a layer of paint, which will positively affect the aesthetics of your invention.

Getting Started

How to make a column at home? The case is the most important component, so let's consider its creation.

The most common and convenient option looks like this:

• Using a hacksaw, you prepare future parts from the selected material.
• Select the components to which the speakers will be attached, and make holes in the central part.

Important! The diameter of the holes must be chosen so that it matches the diameter of the bottom of the device.

• Next, cut out small rings, which are fixed on the holes made. This will help to fix the speaker well. Create a shape that will resemble a plate with a broken bottom. Glue these rings to the finished components.
• Create a few more holes, only in the shape of a triangle. You need to make them around the above rings. These steps will help you achieve optimal sound reproduction, in which all the waves will penetrate the cabinet.
• Take care of the inside of the structure and make small partitions. Choose a length that is identical to the body length. These parts will be needed to fix the phase inverter.
• Make compact ports into which you will later need to thread the terminals.

Assembly step

To connect the body together you will need:

• Fasten all parts using glue and screws.
• Fill the structure with synthetic winterizer.
• Position the speaker in its place.

• Apply varnish to the invention in order to protect the material and give it a decent appearance.

Important! For painting, you can also use special paint for wood, and some of the components can generally be made in any other color scheme.

Sound systems

In fact, columns are not always required. You can create acoustics in a car in another way:

• Make foam podiums. To do this, you need to create a cardboard template and put it on the place where the podium is supposed to be.
• Cut out a solid base. A sheet of plywood or rebar can help you with this.
• Create a base from two rings. The radius of the first should be identical to the radius of the mesh, which is intended for protection. The diameter of the second ring must be observed in accordance with the size of the column.
• Connect the rings using self-tapping screws.
• Make 6 bars to recreate the slope. All parts will need to be fastened together with glue.
• Pour foam into the structure and leave to dry completely.

Important! Instead of sheets of plywood, you can take parts of different wood. For such a task, it is worth choosing only dry materials that do not have visible defects and cracks. The entire structure, in this case, is also recommended to be varnished in order to give it reliability. If you are looking for more efficiency, then secure all components using 2 rails.

Acoustic design does not mean decorating the speakers with antique-style carvings, although this will give the speakers a uniqueness, but a solution to the problems of acoustic short circuits.
The fact is that when the diffuser moves, excess air pressure is formed on one side, and the air is discharged on the other. For sound to occur, it is necessary that air vibrations propagate into space and reach the listener, and in this case, the air oscillates around the basket of the dynamic head and the sound pressure it creates is not very high, especially in the low-frequency region:

More details about the principle of operation of the dynamic head HERE.
The ways of breaking the acoustic circuit are called acoustic design, and each of them is designed to make it difficult for air to penetrate from one side of the diffuser to the other.
There are several main options for breaking an acoustic short circuit. The simplest is the use of sheet material in the middle of which a hole is cut out for the dynamic head. This is called an acoustic screen:

A slightly more complicated way is an open box, i.e. drawer without back wall:

Both of the above methods have too little efficiency, therefore, they are practically not used only in cases where "there is no fish and cancer - fish."
It is much more efficient to use a closed box, and in such speakers special attention is paid to the tightness of the box - any gap in the box will give overtones, since there is both a sufficiently large pressure in the box (when the diffuser goes inside the box) and a sufficiently large rarefaction (when the diffuser moves out) :

The next option for acoustic design is a box with a phase inverter:

In this case, this is a rectangular hole located in a strictly calculated place on the front panel of the speaker system. However, this option can also be done using a pipe:

The advantages of these options include increased output at the frequency at which the phase inverter is calculated, the main purpose of which is to invert, i.e. reverse phase. As a result, sound is emitted into space not only by the front of the diffuser, but also by the back, the phase of which is changed by the phase inverter.
A more complex version of acoustic design is an acoustic labyrinth. The essence of this option lies in the fact that the strokes inside the speakers are located in such a way that resonance occurs at a certain frequency and, as a result, a large increase in returns at this frequency. The calculation and accuracy of manufacturing such systems should be taken VERY seriously, since there is a high probability of the occurrence of "standing" waves in the labyrinth. In this case, the sound quality will be even worse than with an acoustic screen:

An even greater return at the resonant frequency allows you to get a horn version:

The difference between a horn speaker and a labyrinth speaker is that the direction of the sound waves in them changes according to different laws - the horn one either expands conically along its entire length, or exponentially. The labyrinth can have the same window along its entire length, it can expand or, on the contrary, narrow, but always linearly. In addition, for speakers with a labyrinth, both the front and rear parts of the diffuser take part in the work, and for horn speakers, both one and both sides can radiate.
The next acoustic design option is a bandpass or bandpass resonator:

This option differs from all the previous ones primarily in that it radiates only at the resonance frequency and requires the strictest observance of the calculated dimensions.
The last three options are mainly designed for the use of a low-frequency dynamic head, and the previous ones are quite suitable for broadband speakers. Therefore, if the speaker system has others besides woofers, such as midrange and tweeters, then it is not recommended to embed them into the case with a woofer.
In any case, to calculate the size of the speakers, the characteristics of the dynamic head, in particular the Thiel-Small parameters, will be required. If these data are not available, but before taking on the calculation of the dimensions of the speaker cabinet, they must be obtained. There are quite a few descriptions of methods for obtaining these parameters - just use any search engine.
Of course, this is not all types of acoustic design - these are the most popular.
The enclosure dimensions are calculated using special programs for calculating speaker enclosures. Finding them on the Internet, as well as instructions on how to use them, is also not problematic.
When designing speakers, some technological features should be taken into account - if the front panel on which the speaker is installed will be recessed into the case, then additional ribs will need to be made, into which the front panel will actually abut:

If you don’t want to mess with the ribs, then you can make the front panel in such a way that it rests on the sidewalls of the case, which also strengthens the connection between the front panel and the sidewalls:

All this will give the front panel an additional, more rigid connection with the case.
Also, you should not forget about the methods of fastening the dynamic head to the front panel and the pitfalls that you may encounter. Mounting the speaker from the outside is most preferable, since it does not mechanically weaken the structure, however, this method involves chamfering the diameter of the dynamic head and sinking the speaker into the case so that ALL emitters, and bass, and midrange, and treble are on the same line. chamfering reduces the mechanical strength of the front panel and its restoration will require an additional ring fixed from the inside. The relevance of this ring is the higher, the more power is expected to be obtained from the manufactured speaker, and at powers above 150 W it is already 100% necessary:

On the ring, if necessary, it will be necessary to remove the side chamfers so that it does not interfere with the front panel of the installation in the case itself.
When installing the dynamic head, it is necessary to ensure that there are no gaps. If the chamfer is removed by the machine, then the surface is relatively even, it remains only to sand it. However, at home, getting a flat surface is quite difficult. Here, the action of the manufacturers is not entirely clear - it is strongly recommended to install the speaker from the outside, but the sealing rubber on almost all dynamic heads is located for installation from the inside:

To solve sealing problems, you can use a door seal - self-adhesive strips of porous rubber, sold in all hardware stores. The sealant is glued around the perimeter of the chamfer and, when mounting the speaker, completely fills all the cracks:

If the driver is installed from the inside, the hole will need to be chamfered to prevent standing waves. However, such a chamfer weakens the rigidity at the point of attachment of the speaker to the panel (the material turns out to be too thin) and this method of attachment is not acceptable for powers above 50 W without additional structural reinforcement:

It is desirable to use natural material for the manufacture of speaker cabinets, plywood is optimal, but this material is painfully expensive. Therefore it is better to use plywood for building medium to high priced speakers using VERY good quality drivers above 100 watts.
For the middle price category and low power (up to 50W), you can use fiberboard or MDF (the same as fiberboard, only the thickness and density are greater), but it needs to be processed and finalized, or chipboard.

For powers up to 10 W, plastic is also quite suitable, but also using technological tricks.
The first problem, in the manufacture of speakers from plastic, arises when the rattle of the plastic itself is eliminated, especially manifested in the centers of the sidewalls. You can get rid of this unpleasant sub-sounding using thicker plastic, or you can glue additional stiffeners. If the plastic is dissolved by dichloritan, then dichloritan with plastic chips dissolved in it can be used to fasten the ribs. If the plastic does not dissolve with dichloroethane, then it is better to use epoxy glue, preferably Dzerzhinsky production. Before gluing, carefully treat the contact points with coarse sandpaper and do not be afraid that the glue forms rollers at the point of contact of the parts to be glued:

For greater efficiency in suppressing overtones of the body, it is possible to "paint over" the resulting "baths" in 2-3 layers with anti-gravel - a coating used to cover the bottom of cars to protect against fine gravel.

After drying, the anti-gravel acquires the properties of rubber and absorbs sound quite well.
When used as a material for the manufacture of AS fiberboard, it is required to determine the required thickness. If the speaker power does not exceed 5 W, then fiberboard can be used in one layer. Before cutting fiberboard, it is coated with epoxy glue on one side and heated with a hairdryer. Under the influence of temperature, the glue becomes more liquid and impregnates fiberboard to almost half the thickness. After the glue hardens, a rather strong material is obtained, essentially a getinaks, but on the one hand, it retains the sound-absorbing properties of fiberboard. You can cut the WPV with an electric jigsaw, you can glue the workpieces with epoxy glue reinforced with material. To do this, the blanks are folded into the desired design, and grabbed with any SUPER GLUE. Then strips of strong fabric are cut, in our case it is red silk. The width of the strips should be approximately 3 ... 4 cm. The strips are laid at the joints of the workpieces, covered with epoxy on top, and then "ironed" with a soldering iron at 40 ... 60 W. High temperature allows the glue to completely saturate the weave, and also significantly accelerates the polymerization of the glue. True, a certain amount of smoke is emitted during operation, so work must be done either on the street or under the hood:

If the speaker power is higher than 10 W, but less than 20, then it is better to glue the fiberboard twice - first the sheets are glued together, and then the finished case is assembled:

For powers up to 30 ... 35 W, it will already be necessary to fold the fiberboard three times or use a 18 mm thick chipboard (unfortunately, a 22 mm thick chipboard can only be found in old grandmothers in the form of old chiffoniers until the 80s). To stiffen the sidewalls, you can use struts of the "CROSS" type:

For powers up to 50 W, the relevance of using fiberboard is already debatable - it is much easier to work with chipboard, MDF or plywood than folding fiberboard from 4-5 layers. For this, a material with a thickness of 18 mm is suitable, however, you will have to use additional bars that provide a greater bundle of speaker parts among themselves:

Speakers can be assembled using self-tapping screws, but since there is no more power, you can also glue them with epoxy glue or PVA, but it’s better to buy it not in a stationery store, but in a household or building one. This PVA will be called MOMENT-JOINER, water-dispersion glue. Buy on the market recommended only in summer - after freezing, the glue seriously loses its qualities. However, to calm the conscience, it is better to tighten at least a couple of self-tapping screws into each bar.
In the manufacture of speakers, sometimes they make a gross mistake - the MF-HF link is not acoustically protected from the impact of the back side of the woofer cone, which leads to a decrease in the efficiency of the speaker itself, and often to failure of the midrange link - too strong air shocks from the back side of the woofer cone lead to the expulsion of the midrange speaker coil from the magnetic gap and jamming, the coil is jammed.
Much more often, they forget to subtract the volume of the protective casing of the midrange-tweeters from the total volume of the speaker, as a result, the internal volume of the speaker is less than necessary and the final characteristics are greatly blurred - the resonant frequency of the phase intertors rises noticeably, which leads to unwanted overtones.
When assembling speakers with a power of up to 100 W, you can also use either chipboard or 18 mm thick plywood, although of course it is better to look for material 22 mm thick. To exclude the occurrence of resonances of the sidewalls of the speaker cabinet, additional bars are also used through which parts of the speaker are fastened. It will not be superfluous to install a "cross" and an additional washer for fastening the woofer of the dynamic head, as well as processing the speakers from the inside with sound-absorbing materials, for example, pasting with foam or foam plastic 5-10 mm thick, just do not forget that pasting will "eat" part of the internal volume and it must be corrected for when calculating the dimensions of the case.

Mounting foam gives the best results, since the thickness of the applied layer can be controlled by the speed at which the foam is released from the can. If the foam is released VERY slowly, it is very dense and the increase in volume is not very large. If the foam is released VERY quickly, then it turns out to be much looser, and when solidified, it greatly increases in volume. If foam is applied to the sides of the case from the front panel, increasing the foam output when approaching the rear wall, and at the front panel providing a minimum foam output rate, the internal volume of the speaker will take the form of a pyramid lying on its side. Such tricks completely solve the problems of standing waves, since there are no parallel planes inside the speakers, and the unevenness of the frozen foam only enhances the pyramid effect. When using this technology, you should be more careful with the calculations of the dimensions of the workpieces - the internal volume decreases VERY strongly and this requires a serious increase in the speaker cabinet.

The ribs for fastening the sidewalls, in addition to the screed with self-tapping screws, are recommended to be glued, as in the previous version, but there are several more options for adhesive masses:
- epoxy glue mixed with fine sawdust, or, better, wood dust;
- MOMENT-JOINER, but before screeding, the applied glue should be allowed to dry a little, until the consistency of butter at room temperature is obtained. This will more fully fill with glue all the irregularities between the parts of the speaker;
- polyurethane glue, for example MOMENT-CRYSTAL, which also needs to be allowed to dry a little. After assembling the gluing site, it is necessary to warm it up thoroughly with a hairdryer, which will lead to the formation of small bubbles in the adhesive mass, and the mass itself will more densely fill the irregularities between the contacting body parts;
- automotive sealant of domestic production, namely domestic, since after hardening it is much tougher than imported sealants;
- mounting, polyurethane foam. Before applying to the parts to be glued, the foam is "released" onto an unnecessary piece of plywood or DPS, and then thoroughly mixed with a metal spatula until it "shrinks", i.e. until a mass similar in density to thick sour cream is obtained. After application and screeding, the foam will still expand a little and completely fill all the irregularities at the point of contact of the speaker parts.
After gluing, the parts must be allowed to dry thoroughly for 20-26 hours.
To increase the volume at the same output power, you can use "double" dynamic heads - using parallel or serial connections of two identical speakers for the low-frequency link. In this case, the total area of ​​the diffusers increases, so the speaker can interact with a much larger amount of air, i. create more sound pressure and from this the subjective loudness is much higher:

Here it should already be noted that the use of a large number of speakers, including for dividing the sound range, begins to introduce some troubles - it is quite difficult to achieve signal phasing in those places where the frequency response of speakers adjacent in range intersects. Therefore, one should not chase after a large number of bands for a home-made speaker - this porridge can be very spoiled with such oil.
It is better to make speakers with a power of 100 to 300 W from plywood, and you will have to look for plywood 22 mm thick. AC is also assembled using stiffening bars, which are glued. It is better to give the bars the shape of equilateral triangles, where the legs will be attached to the sidewalls, and the hypotenuse will be directed inside the body.
If you cannot find plywood of this thickness, then you can use plywood 8 mm thick glued three times - the final thickness of the material is 24 ... 25 mm. Adhesive masses are listed above.
As a technological advice, we can only recommend that you first cut the necessary blanks and only then glue them, and immediately tighten them with self-tapping screws.
When installing a "cross" inside the AC, which will not be superfluous, it is better to round off the corners of the stacking bars - already quite large volumes of air are already moving and turbulence may occur around the right corners of the couplers. It is also recommended to "round" all internal corners, using plasticine or applying several layers of thick anti-gravity.
Another type of acoustic design is the separate execution of cases for each speaker. In such speakers, passive filters are not used, and the signal is divided into ranges immediately after the amplifier volume control. Then the divided signal is fed to three separate power amplifiers, which actually work each on their own speaker:

It would be unfair not to mention the "fillers" often used in speakers - small rinks of sound-absorbing material lying inside the speaker. Such rollers make it possible to slightly increase the calculated internal volume of the hull, however, in order to properly manufacture such a "filler", it is necessary to know its acoustic properties. It is rather problematic to get the characteristics of the "filler" in a home environment, so it remains either to refuse to use the "filler", or to find out by experience the required volume and the material used (usually fluffed cotton wool, batting, sentipon).
With powers from 100 W, it also becomes relevant to ensure the stability of the speaker cabinet, since quite a lot of work is already being done to move the diffuser and the air is actively "resisting". It is also desirable to break the mechanical connection between the bottom of the speaker and the floor on which the speaker is installed. For these purposes, they usually use either tripods, which are problematic to make at home, or they use steel spikes screwed into the bottom of the speaker:

At powers above 200 W, it is desirable to strengthen the front panel of the speaker and it is desirable to use materials of different structure, for example, if the front panel is made of plywood, then a chipboard sheet is glued on the inside, the thickness of which is 1.5-2 times less than the thickness of the panel. Such a combination of materials ensures the absorption of vibrations in a larger sound range just due to the heterogeneity of materials.
For greater stability of the speaker, its mass can be increased by smearing the bottom with polyurethane mounting foam and laying a couple of bricks in it, covering them with the same foam on top. After the foam has hardened, it is better to cut off the irregularities with a clerical cutter. The "stolen" internal volume must be taken into account when calculating the dimensions of the future nuclear power plant.
For powers over 200 W, it is better to use combination materials - all speaker parts are glued together from 18 mm chipboard and 18 mm plywood. Plywood is used as the outer layer, while chipboard is used as the inner layer. Such a trick allows you to save a little - chipboard is much cheaper than plywood. Inside the speakers, it is desirable to glue with sound-absorbing material, for example, triple-stitched batting, double-stitched quadruple sentpon (sentipon can be double and quadruple), 5 ... 10 mm foam. The different structure of tightly glued materials of different structure eliminates the problem of resonance of the cabinet itself.
It is better to additionally tighten the corners with metal corners - this will add rigidity to the structure and protect the speaker corners from damage - the speakers are already quite heavy and during transportation various blows are possible from which it is the corners that most often suffer.

For powers closer to 1000 W, the thickness of the material should already be quite large, for example, two layers of plywood 18 mm plus a layer of 18 mm DPS, the total is already 54 mm, and the DPS is glued between the plywood layers, however, similarly, the speakers are already moving into the category "for scoring", therefore quality can be sacrificed in favor of mobility. Based on this, you can use double 18 mm plywood, installing a "cross" inside.
It is not difficult to see that with increasing power, the thickness of the AS walls increases. This is primarily due to the fact that it is necessary to isolate the air moving inside the speaker from the listener. However, we should not forget that the speaker cabinet can also resonate. It is to eliminate this trouble that it is better to use internal pasting of the cases and minimize the overtones obtained from resonance. It is not difficult to check the resonant frequency of the case yourself. To do this, it is necessary to tilt the speaker at 20 ... 25 degrees and throw a rubber mallet on top of it from which you first pull out the handle. The slope of the AC is necessary so that the blow is single and the mallet bounces far to the side.
A microphone fixed to the speakers (membrane hole to the body) and connected to any linear amplifier on the oscilloscope screen will draw both the moment of impact and the aftersound that the body itself gives. The test is, of course, rather rough, since in reality the "shock wave" comes from the inside, and during the experiment from the outside, nevertheless, based on the results of this test, one can judge at what frequency the body itself resonates and how quickly the damping occurs:

An ideal speaker does not cut and the moment of impact attenuates immediately, almost instantly, but the walls of an ideal speaker consist of concrete 1 cm thick for every W of power and such an speaker is more suitable for ridicule than for exploitation:

The finish of the speakers can be very different, there are no strict requirements here. If the case is made of plywood and the pattern is rather sympathetic, then the case can be sanded, and then covered several times with a colorless varnish:

You can buy valuable wood veneer and paste over the speakers with veneer to match the color of the furniture in the room:

In car audio salons, the so-called acoustic fabric, which is a synthetic felt, is sold. The material sticks well and stretches, which will allow you to finish the speakers at a fairly high level:

After sanding the body, you can paint it with car paint, just let's make an amendment for the fact that car enamels dry at high temperatures. Therefore, you will have to use the special IZUR hardener, the mixing proportions are written on the hardener packaging, although it is better to add it 10-15% more than the proposed proportion:

If the body is carefully sanded and sanded, then it can be pasted over with a self-adhesive film sold in OBOI stores, but this material is rather delicate and it is worth using it if there is confidence that the speakers will stand in their place for ten years:

If you plan to transport your loudspeaker frequently, it will be very useful to provide appropriate handles. This is especially true for small speakers, which you want to take two at once, and for large ones, which simply have a lot of weight.

How to independently assemble an active speaker with increased efficiency at low frequencies is described.

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