Making speakers with your own hands is within the power of someone who knows how to handle a soldering iron, and also understands electrical circuits. To work, you will need a large number of parts that can be borrowed, for example, from car radios. You will also need material for the manufacture of speaker cabinets. Usually, wood is used for these purposes, but you can even use a plastic case from worn-out acoustics. Before you sit down with a soldering iron and etching a printed circuit board, you should choose a design, a microcircuit, and the capabilities of an acoustic system.
What do you need from acoustics?
It's nice when the sound reproduced from a personal computer sounds in the entire audible range (from 20 Hertz to 20 kHz). To emphasize certain frequencies, you need to use special filters. Most of the cheap speakers that can be found on sale reproduce sounds in the range from 50-100 Hertz and up to 15 kHz. From this, the sound seems incomplete, ugly. Therefore, DIY loudspeakers must have higher performance to meet your needs.
Immediately decide which frequencies you plan to emphasize, whether your amplifier will have the ability to manually adjust. But if you decide to take the easy route, it will be enough to filter out low and high so that devices that reproduce this spectrum work in parallel with the main speakers. You've probably heard words like "tweeters" (small speakers that filter high frequencies) and "subwoofer" (large wooden box, which houses the bass speaker). These are the ones you have to make yourself.
What do you need for a subwoofer?
Without a quality box, it will not work. Surround sound is created by air moving inside the box. Moreover, the air drives the speaker cone. So, you need to make a closed box with one air outlet. Since you are making speakers for your computer with your own hands, there is no need to use huge speakers that are used for car audio. The ideal option is car acoustics used as standard, which is installed in the front. Small diameter speakers, rubberized diffusers, soft and elastic. This is exactly what is required for a subwoofer.
Of course, it will not create strong air pressure, but for a small room it will be enough to emphasize low frequencies. You will also need a bass amplifier, there are a lot of these on the radio markets. If possible, you can remove it from an old car tape recorder. The output power must be at least 20 watts, and the power supply of the microcircuit is preferably unipolar. But the most important thing is the low-pass filter (LPF), because how to make a do-it-yourself speaker with a subwoofer without this node will not work. Do not clutter up the design with complex low-pass filters on microcircuits and operational amplifiers. A passive filter assembled from resistances and capacitors is enough. Depending on their parameters, frequencies are cut off.
How to make a subwoofer box
For the manufacture of the box you need to use durable wood. Chipboard or fiberboard is ideal, its thickness should be no more than 5 mm, so that the design is as light as possible. If there are old Soviet TVs in wooden boxes, then you can make a good box out of them. Cut out all the structural elements with a jigsaw. Do-it-yourself acoustic speakers must be durable, so do not spare glue and self-tapping screws for fasteners. The front part, on which the speaker is installed, is attached last.
To stiffen the box, use wooden slats triangular shape. Try to glue all small cracks and gaps. After all, the air in the subwoofer will move, and you need it not to come out of the slots, as the sound is spoiled because of this. In the back of the box, you need to drill a hole for the wire, a connector for connecting to the amplifier is mounted on the outside. It is much more convenient if the self-made sound speakers are compact and without external blocks.
How to make a power supply
As mentioned above, you should not take a chip with a bipolar supply for the design. The reason is the complexity of the power supply, it is not easy to get the current necessary for operation. Therefore, it is best to make designs that can be connected to a unipolar voltage of 12-24 V. And subsequently repairing the speakers with your own hands will be much easier, unless, of course, any breakdown occurs. The power of the transformer should be slightly greater than the power of consumers - all amplifier circuits.
The best option is to make one power supply for all devices. For the effective location of all acoustic units, it is worth placing both the power supply, and the low-pass filter with an amplifier for the subwoofer, and the ULF for the main speakers and tweeters in one case. This will allow ergonomic use of the equipment, and the number of wires becomes minimal. On the back wall of the subwoofer, you need to install connectors for connecting the main speakers and tweeters. But keep in mind that the subwoofer is a source of vibration, so soldering must be done with high quality, and fastening to the case should be done using rubber washers.
DIY speakers: amplifier and power supply
The amplifier and power supply can also be embedded into the subwoofer case to save space, and connectors for connecting "tulips" can be installed on the outside. The hole is filled with sealant, after which the front side is installed. It is also mounted first with a sealant, and then attracted with self-tapping screws. After the box dries, it must be covered with a suitable material.
Can be used as a power supply a simple circuit: transformer, rectifier bridge and 2-3 electrolytic capacitors. Such speakers for a computer, assembled with their own hands, will work great, the sound will be clear and pleasant. If there is a slight buzz, then increase the capacity of the electrolytes. In the absence of elements with a large capacity, several pieces can be connected in parallel, then the total will be equal to the sum of all capacitors.
How to make basic speakers with your own hands
For the manufacture of the case, you can use both wood and plastic. It is better to give preference to the first, since when it is used in acoustics, the sound quality improves. If you are too lazy to cut wood, then you can ennoble the speakers from the old radio or use them without alteration. The amplifier and power supply will be assembled in the subwoofer box, so all that remains is to connect the speakers to the desired connectors. Therefore, if you have two speakers from the music center, you can safely use them.
If you decide to do everything in at its best, then, by analogy with the subwoofer box, you also make two cases for the main speakers. If desired, they can also be pasted over with attractive material. Pasting with thin felt, for example, improves the sound quality of the speaker system. In these speakers, it is most reasonable to install two speakers each - for medium and high frequencies. This will save wires for connection, and provide a more attractive appearance of the entire system.
Production of a printed circuit board for amplifiers and rectifiers
Perhaps no less laborious process, which will take a lot of time. If the scheme you have chosen is simple enough, then you can apply a pattern to the foil material using a permanent marker. Pre-treat the foil with car battery electrolyte or hydrochloric acid. This will degrease the surface and improve the etching process. If the PCB pattern is complex, then it is better to use laser ironing technology and software for drawing tracks. Here's how to make a column with your own hands, namely a printed circuit board for it.
In the program, you outline the location of the elements, draw paths, and then print the resulting image on laser printer with maximum black saturation. Paper is better to use glossy. Then lay the drawing face down on the surface of the textolite foil, fasten the paper and wrap it in a clean rag. The heated iron now needs to be driven over the rags so that the pattern is printed as accurately as possible. This procedure is carried out within 10-15 minutes. After its completion, moisten the paper in water, all excess will go away, and only toner will remain on the foil. If necessary, you need to draw the missing elements with a permanent marker.
Board etching
After the transfer of the picture is completed, you will need a solution of ferric chloride. Most radio amateurs use it, since the etching process with it takes little time. If using a solution blue vitriol and salt, then etching can take a day or two, depending on the concentration of substances. It also happens that a solution of ferric chloride corrodes copper poorly, so to increase the etching rate, you need to heat it. Just try not to miss the moment when the tracks are freed from excess metal, otherwise the part of the foil that is under the toner will be destroyed.
In principle, you can make music speakers with your own hands without etching printed circuit boards. There is a hinged installation, which is much easier to do. But it's a beautiful board with correct installation it looks much nicer than the wires and conclusions of the elements assembled in a heap. And the possibility of interference in the case of surface mounting is much higher. After etching the board, it must be thoroughly washed and dried. And only after removing the toner layer with a solvent or alcohol, you can proceed to install the elements.
Mounting elements on a printed circuit board
Now you just have to outline the location of all the elements on the surface of the board. First, make marks in those places where you want to make holes with a drill with a diameter of 1-1.2 mm. The lesson is not easy, because with strong pressure, you can simply break the drill. To improve printed wiring, it is necessary to tin (cover with a layer of tin) all the tracks of the board. To do this, you need to treat them all with a solution of rosin, after which, with a heated soldering iron with tin, go through each one so that the solder reliably adheres to the copper surface. Excessive heating is not needed, as there is a risk that the foil will begin to peel off the textolite.
Before installing the elements, their terminals must also be tinned. Only in this case, do-it-yourself computer speakers will have the highest possible reliability. In the presence of vibration, the soldering can collapse very quickly, the contact will disappear, and the amplifier will stop working or will work, but with a wheezing, unstable.
Conclusion
As you can understand from all that has been said, you can make high-quality acoustics from any material that is at hand. Pay only attention to its condition, do not use rotten wood for a subwoofer or speakers. The elemental base of bass amplifiers is very small - one microcircuit is enough, which provides an output power of 10-20 watts in two channels. Simple music speakers, designed with your own hands, will serve you for many years, and the sound quality will allow you to enjoy both music and films with special effects.
I dedicate this material to all DIYers and wish them good luck in their work.
Start
Dear friends, allow me to introduce myself. My name is Yuri. He received his name in honor of Yuri Alekseevich Gagarin, like many boys of that period. That's how popular he was when I was born. Apparently, the energy of that time and the name of the first cosmonaut was transferred to me to some extent and became a part of the soul that required activity. During the school years, the activity was multidirectional, but did not include studies. In life, this did not become a hindrance. Graduated from the Technical University with honors. I have not changed my profession, chosen on the basis of the maximum complexity of the specialties offered by the university I entered, and I still earn it. They taught me to be a designer of hydraulic machines and means of their automation.
In his free time from work, all sorts of hobbies did not let go further. In another spiritual outburst that happened quite recently, I discovered a wonderful Audiomania store, in particular, its “Do It Yourself” section. What I saw there on my first visit was a dream of youth. True, in those days it was impossible to imagine. The assortment of this store opened the door for me to the world of ideas implementation. I think, as for many other obsessed with ideas, people.
In addition to my passion for audio technology, which accompanies me through life, I love photography, I read science fiction (necessarily about space travel - that same energy works out). And one more hobby - for almost a dozen years I have been making wooden furniture. Now there is already a serious experience of a cabinetmaker, which allows him to make furniture professionally.
Creating acoustics, which will be discussed, is one of my old hobbies. But, the accumulated experience, today's opportunities and new desires have made it possible to set ourselves a difficult task - to create acoustics for the home, conveying the dynamics, scale and emotionality of a concert performance of music.
To all readers - my immense location and best wishes.
Yuri Kobzar
I am an amateur. I will try to write only about the specifics. share mine practical experience to create high-level acoustic systems. I address this information to the same amateurs who like high-quality sound, who enjoy not the background, but listening to music. People who are in the world of sounds, have preferences and favorite records.
In the spring of 2017 something happened to me. In the evening, on the veranda, a bird's chirp reached my ears, a real warmth blew, somewhere it turned green, the first vegetable aroma flew in, I wanted to sip wine and listen to music. Without analyzing (one can attribute everything to the fluctuations of the soul), I felt the need, and I had the idea to get a good sound for the house. Moreover, there is “music” in the house. But at that moment, the term good sound suddenly took on a different meaning. Memories popped up in my head from casual listening to music in a store (in a high-end room), a great opportunity to experience the highest quality sound with a few friends. All this happened years ago, but the need for a good sound took shape precisely in the spring of the seventeenth. Despite the fact that a reverent attitude towards “good” music has accompanied me all my life, and almost always there was an opportunity to listen to sound of decent quality, it suddenly became clear: music sounding from acoustics should not just be pure, detailed, powerful, deep, natural, bewitching or even amazing (the body at high volume is a joke). The sound reproduced by acoustics should convey emotions: soloists and musicians, and all those who prepare the recording for us - listeners.
According to preliminary estimates, possibly overestimated, it turned out to be too expensive to buy such equipment. I didn’t want to exchange for a good affordable one. Thus, the task arose to build the acoustics of the highest class available at home. Without laboratories, high-precision measurements, but in order for the breed, the solidity and elitism of the sound was undeniable. To create such an impression from listening.
As a small digression, it should be said that the idea had a base. I had certain skills at my disposal: in my youth I built acoustics in a “closed box”. I was happy with her sound. Various transistor amplifiers were soldered, one model is extremely high quality. Now, in addition to the former half-forgotten knowledge, skills and experience, a love for making furniture from wood and a certain set of carpentry tools have been added. Additionally, I wanted to get a high-quality tube amplifier. In order to shorten the implementation of the plan, he offered the participation of his friend, an enthusiast and homemade, who has the base of the radio department of the UPI (Ural State Technical University). We agreed that acoustics (rebounds, calculations and implementation) would be my task, lampovik is part of it.
From this position, they began to "shake the old days."
Choice
The question of building AS was started with the study of theory and related materials. Before me, as well as before many builders of their own acoustic systems, the question arose of choosing an acoustic design. Knowledge, information, opinions began to be accumulated and systematized, but the answer to the question about the type of acoustic design of the speakers remained open. At this time, three broadband heads 75GDSh3-1 became available to my partner. A local recreation center decided to throw away two stage subwoofers that had worked for over 30 years. Each had two speakers. In one of them, the speaker failed, hence the decision to throw it away. Listening to the speakers "on the floor" confirmed the "no sound" expectation. Listening in the native subwoofer case - the assessment has not changed. Almost without enthusiasm, I began to dig the Internet on the topic of using speakers of the existing type in speakers. Materials of comrades who had already built speakers based on these speakers were quickly found. I liked the variant with "tekuvete" (tqwt) Voigt's pipe - I am attaching the material, authorship has not been established, see link). I liked this option, including because of the "open case", to which some sympathy has already arisen. Why: no speaker damping or minimal damping as needed. In other words, the dynamic head is not obstructed during operation, and this, as I understand it, means a minimum of conditions for creating external resistance and, as a result, distortion. Still, the resonant frequency of the speaker in the housing with the pipe does not change. This, in turn, should ensure the reproduction of a richer bass component, which is the basis of the rhythm, providing surround sound and enhancing the psycho-emotional perception of the musical program. With internal resistance (after listening to the speakers), fear of getting a weak result and, nevertheless, with hope, I bought three sheets of 12mm construction plywood to repeat the proposed design in the material. The refinement consisted in the use of radius transitions in each corner (bent plywood for the first time), the installation of a stiffening rib inside (taking into account the dimensions and thickness of the material) and the device of a rigid removable back wall for the convenience of work on subsequent possible damping.
I do not give the manufacturing technology. Open up too. Taking into account my experience of working with wood, I believe that each craftsman who undertakes the manufacture of such a structure will have his own specific design and manufacturing work. Specificity is associated with conditions, skills and a set of tools. I'm used to working with glue, refusing metal fasteners (except for a removable back wall). This ensures the absence of technological rails that take volume, give additional geometry in the sound channel, which, from my point of view - certified hydraulics - is not good for the movement of a sound wave through the channel. And the task, by the way, is to create conditions for its smooth, laminar (there is a term that means the absence of turbulence) movement through the channel. This reduces the chance of overtones that are unnecessary for high-end sound.
The sound of the built speakers surprised me right away. Powerful, bright, beautiful and different from my branded three-way bass-converter (FI) speakers of the English brand. Considerably excellent. Emphasis on the word "excellent". Surprise was intensified by the fact that in the same place - England, the intelligence of engineers and large-scale production, and here is a 35-year-old miracle in a plywood box. After the first surge of emotions subsided, it became clear that one speaker was not enough for this speaker. Not enough tops and ... bottoms. The bass is low, beautiful, with many shades (which is not heard on FI) and, at the same time, weak. You can persuade yourself to such a sound, but the disadvantage is noticeable.
Having doubts about the ability of this speaker to play bass in a full-range speaker, he built a narrowing maze - a transmission wave line (TVL). According to reviews on the network - this is just what you need. I describe without details and arguments in favor of such a decision. I do not give recommendations and dependencies for the construction of TVL. Everything is on the Internet. This design was made more technological: with legs, without fillets. It should be noted that the speakers turned out to be more compact in size. Here is her cut.
Many authors in the network mention the importance of correctly made calculations of the transmission-wave channel, the absence of fundamental errors, the complexity of the design and the need for its exact repetition during manufacture. At the same time, apart from the geometry and the rules for choosing speakers, there is actually nothing in their approach. When drawing the design of speakers with TVL, I was accompanied by a feeling of deep understanding of mechanics, but not acoustics. He did everything on faith. After all, many people have already shared their practical experience, the results achieved and photographs. Many were satisfied with the received sound. It's a weighty argument.
Again took construction plywood. This time, two sheets, taking into account the remnants of the previous version. Produced quickly and accurately. It should be emphasized the excessive rigidity of the hulls of such structures, even when using 12mm plywood.
So, the listening experience is very good. The disadvantages are the same. If the lack of treble is the design of the speaker, then the lack of bass is the case. It should be said that the bass has become more expressive and emphasized. This was noted independently by all participants in the audition. The surprise was this. At first, each column was listened to separately. I wanted to hear its capabilities, compare with another option. Moreover, the first experiment of repeating the design gave only one column. Then they were connected together. The effect was amazing. There was not only a panorama of sound, a stage. First of all, the sound itself has changed. His power, openness, lightness stunned! Yes, later, while listening to an unequal pair of speakers, I had to raise the treble and bass on the amplifier. But the sound was not just beautiful. He held and pulled. Favorite tracks sounded like listening to them for the first time. On many, shades of bass and mids began to be heard, the existence of which I had not even suspected before with English floor speakers. A friend of the wife, who was present with her in the house in the next room while testing a pair of speakers at different volumes and styles: chamber music, jazz, electronics, leaving, said that she had been to the Philharmonic or to a concert. This phrase was not a delicacy towards the owners, but similar to the truth. The spread of sound through adjacent rooms turned out to be a pleasant surprise. This will be an important point when receiving guests for creating a lung unobtrusive musical accompaniment in several zones at once. The equipment began to turn on with each pass by. And, in the end, after three days, he finally gave up and asked the future owner to take this test version of the acoustics home to listen to until the time comes for the production of front-end speakers.
The conclusion was this: if there was a choice of speakers in the store, the sound of the received speakers (not a plywood look, of course) would suit me completely. About the received sound it is said modestly. The sound is grand. When a couple of speakers are playing, the high frequencies are practically enough. This is not sand, the speaker cannot reproduce it. But what he reproduces already met our requirements. The resulting sound shocked, turned something inside, there were lumps in the throat. Without exaggeration. There was only one "splinter" - the bass on the amplifier was twisted to the maximum. Nevertheless, the owner of the speaker also liked the sound. Later, it was even decided to make the final version on the basis of TVL: the dimensions and sound of the bass took over.
ordeal
In the meantime, the issue of creating an AU for "own use" has become topical. It is highly likely that after the speakers on the speakers 75GDSH3-1, the search would have come to an end good sound. Pretty quickly it happened, and hit almost to the point. Fortunately or unfortunately, but the second pair of heads 75GDSH3-1 or 3-3 was not found. Crawling on the World Wide Web, collecting and analyzing information, continuing his studies, he began to closely examine the acoustics of the English company Tannoy. An ideal speaker is a device that can linearly reproduce the entire spectrum of sound from a single point. And life is full of compromises. Creating acoustics is the search for the optimum among many compromises. Each speaker option solves its own problems and becomes a tool in the hands of marketing: a successful combination of speakers in a speaker system, beautiful (correct) frequency separation, bulging bass, a clattering tweeter, a unique design, the use of precious wood in the case, or simply a well-known brand. All together or separately is designed to convince the buyer of the correct choice. The older Tannoy acoustics (Westminster and Canterbury) interested me in appearance, and it is built on just one speaker. Sound from one point! The old, well-known company, which retains its leading position to this day, has its admirers. I soon learned that the Tannoy acoustics are still two-way, but the bass / midrange and tweeters are coaxial. In engineering terms, this solution turned out to be very attractive. Great solution. In the same network, I read the praise of some and the disappointment of other owners of this acoustics after moving it from the salon to my home. I recalled that I myself appreciated the sound of Tannoy a few years ago in the listening room of a store. Then I liked the Cornwall version of the American Klipsch more. And another understanding came - good acoustics do not always sound good (on different musical material and in different rooms), and this fact had to be somehow taken into account when designing your own speakers. For example, Tannoy is equipped with two knobs for adjusting the midrange and treble.
Given the need to accept compromises, the intention arose to create something like Tannoy Westminster or Canterbury. It turned out that at "affordable" prices in China, you can order complete copies of the Canterbury speakers. They even offer their speakers. There were no reviews about the quality of the system and sound. Decided not to risk it. After analyzing the accumulated information, I began to search for the design of Tannoy acoustics. I found something for the Westminster speakers, and in one Polish chat - 150 photos of the process of making a copy of this acoustics. The decision to repeat almost happened. Stopped scheduling the installation site. Still, Westminsters are built for the big space. Of course, you can install them in the room of an ordinary apartment, but the discrepancy between the dimensions of the living space and two huge speakers catches your eye. I have a private house and some free space is available for placement. However, this option (with a creak) was rejected from implementation. Because of the dimensions and, because of the inaccessibility of the native Tanno speakers (as well as their high cost). In addition, the design will be largely at random (exact drawings are not available). Expect high quality sound, in this case, it is not necessary. I wanted to have a controlled process. The study of the issue continued, and the coaxial tannoevsky speaker did not give rest. Frankly, I continued to look for reasonable opportunities to purchase Tannoev heads until I came across the Spanish Beyma. This manufacturer offers the design of a coaxial two-way speaker that interested me. Here is a photo of a coaxially installed tweeter in the center of the woofer.
Bandwidth performance was not as "smart" as the Tannoy. But, I remember, when, in my youth, friends and I connected different heads to the sound frequency generator, we were surprised at the limited range of audible frequencies. The low-frequency effect was especially interesting: significant movements of the speaker cone are visually observed, and at the same time, there is practically no sound. Therefore, having doubted as it should, I chose the speaker 15XA38Nd of the Spanish Beyma with a neodymium magnet. Of course, I was embarrassed by the lack of traces of the use of this speaker for home acoustics on the network: both on Russian and on Western resources. I was confused by the power rating of the speaker: 350 W for low frequencies and plus 90 W for high frequencies. Settled head size 15 inches. The lines read by someone on the net remained in my head: “... the transfer of the grandiose nature of the sound of a concert scale is achieved by heads of 12 inches and above.” With this statement, I agreed in my heart. Yes, and the parameters of Westminster and Canterbury confirmed the correctness of this phrase. It was also clear that the dimensions of acoustics with these heads would be significant. But the characteristics of the speakers, their declared sensitivity of -99 dB, pushed the last doubts. The decision to take the risk was made. For those who are interested, you can find the characteristics of the head on the net or Audiomania.
Speakers ordered, had to wait almost three months for delivery. At this time, the issue of acoustic design returned again. Without digression, I will say that the material “Rogozhin's Labyrinth” seriously helped to approve my choice. It can be easily found on the web. I do not provide a link, since the author asks for prior approval (although the material is available for free). But there, thanks to Rogozhin, both justifications and practical advice. I would venture to make a statement: this is the only material without water, to the point, with a full set of recommendations for a practical outcome. Hence its popularity.
After this stage, the ordeal with the decision was left behind. Ahead were the pleasant hardships of night acoustic calculations and the design of the speaker cabinet.
A little "around and around"
All of the above, conditionally briefly represents the path traveled. I described it for those who are interested in creating a high-quality speaker system with their own hands, who are faced with similar issues. This describes the process of developing speakers from scratch, and the path was completed all the way to the creation of a prototype. Anyone who wishes can also go all the way, more consciously. Someone will be able to cut corners on it.
A few words about Rogozhin's labyrinth. The attractiveness of this design lies not only in the ability to obtain excellent acoustic results (I say this already with understanding), but also opens up the possibility of designing the exterior and internal architecture in the widest possible range. Ultimately, this technology allows you to create speakers "for yourself." Such an indoshiv. It is extremely convenient and attractive. Probably, everyone understands the difference between a purchased ready-made cabinet and a built-in or shaped according to specific requirements. Functionality, adaptability of the second option is higher. If we take into account the possibility of creating an appearance according to your requirements, linking the appearance of the speakers, color with the interior in the placement area, the value of the option further increases.
Frankly, the understanding of the purpose in acoustic calculations according to Rogozhin's recommendations should be clear. At the first stage, this is achieved by following the instructions given in the material and, already at the second stage, ... by gaining experience. In order to achieve the desired result, I had to perform a lot of acoustic calculations to obtain optimums and build six experimental options in order to reach the seventh - final. Comparing the result obtained in material and sound, you can clarify the calculations performed and make the right choice of option, fitting it to your preferences, providing great sounding speakers.
For those who are not tired
Quite a practical side. So, the choice of dynamic heads is behind, the choice of construct (maze channel) too. On the recommendation of Rogozhin, I installed the Hornresp program from an Australian developer. After following the step-by-step instructions, I got the first result. I will say this, almost blindly, I had to perform at least a hundred calculations to meet all the requirements. What you need to strive for - instructions are given by Rogozhin. Next, I share my own experience.
First of all, a photo of the attempts made to find the desired sound:
Here are five enclosure options for one type of speaker. All options, except for the last one (this is the sixth option, obtained by altering the fifth), are made in the amount of 1520 mm in height (the height of the plywood sheet). The width and depth of the hulls are different and depend on the design section of the channel. The internal architecture is also different. The first option (the right body in the first photo) is made of 15 mm plywood. Hull weight - about 70 kg (without finishing). All subsequent ones are 12 mm plywood and weigh from 35 to 55 kg. Light vibrations of minor surface areas on 12 mm thick acoustic cabinets are present at a supplied power of 100 watts. To be honest, the developed sound pressure at such a power in a limited space cannot be sustained for a long time. It's good that there are no neighbors behind the wall.
Thus, at a comfortable volume level, vibrations of the case and overtones are not noted. By the way, no overtones were noted at any volume level.
Crossover Debugging
The approaches and features of creating the acoustic design of speakers have been described above. It should be noted that the dimensions and weight of the speakers are impressive, the power of the speaker used is high. When speaker systems were conceived, there was a belief that they needed to be listened to with an input power of 0.5 watts. This circumstance was one of the limitations when choosing a speaker. There was doubt that a powerful speaker would provide efficient operation with low power input. Despite the available headroom, built speaker prototypes perform this function, providing great sound with minimal power input. And, without detracting from the grandeur of the sound.
Currently, the received speakers are connected to a Sony amplifier, in which the volume level is calibrated in decibels. Late in the evening, when there are no extraneous sounds, the acoustics sound great and bright at a volume of minus 66 dB. I also note that the power reserve of the speakers guarantees the operation of the speakers with minimal linear distortion at any comfortable volume level.
So, debugging the sound in the crossover.
Initially received a set of speakers and ordered from the manufacturer (Beyma, Spain) FD-2XA crossovers for these particular speakers disappointed me. The first inclusion at low volume led to complete bewilderment. The sound was just terrible. At low volume, the bass was almost non-existent. As the volume increased, they turned into something completely absurd, emitting an incredible muttering. There was no music as such.
After a 3-4 hour run at high volume (70-90 W), the speakers started working (warmed up). However, the dissatisfaction with the sound did not disappear. Neither sincerity, nor grandiosity of basses, nor desirable emotions. Only commendable sound detail.
As I mentioned earlier, sound development was carried out in two directions: search optimal parameters maze and crossover work. The developments in the labyrinth are given above. Crossover also taught its lessons. His scheme was found on the Internet. It was a first-order filter with a matching circuit for the input impedance of the low-frequency loudspeaker. The crossover frequency, according to the Beyma website, is 1800 Hz.
Of course, I could describe in detail all the searches and turns of the settings of the obtained filters, but something tells me that such a presentation would be boring and uninformative. I'll put it in the thesis.
- It turned out that after turning off the capacitance of 15 microfarads, bass reproduction became more pleasant.
- Tests have shown that on some musical compositions acoustics gives audible distortion. It was possible to establish that the distortion is introduced by the HF part of the speaker. Distortion disappears when the high-pass filter cutoff frequency is shifted to 2500 Hz and above.
- To reduce the brightness, one might even say, the "clamor" of the speakers in the midrange range, instead of a capacitance of 2.2 microfarads, it is better to use a capacitance of 0.68 microfarads.
After such changes, the sound became very good, but still, not quite satisfied. An attempt to leave the woofer without inductance L1 did not further improve the sound of the speakers. Nevertheless, the uneven frequency response of the speaker needs to be compensated. The manufacturer's inductance is kept in place. Her influence is well felt.
And so, after a long listening to various genres, after trying to vary the values of the remaining filter elements right during listening, “on the go”, so to speak, turned off the RC matching chain (8.2 ohms and 8.25 microfarads - indicated in the diagram). There was an amazing effect. Feeling the sigh of a speaker who has gained freedom, previously held by a kind of noose. The previously held sound escaped, flew, became light and noble. It is impossible to convey in words the newfound lightness and virtuosity of the renewed sound. Exactly the sound appeared, from which an internal response arises, chills go through the body, and pouring music fills all the cells of the brain.
It should also be noted that the inductors of the Beyma crossover are not serious. They are wound with 1mm copper wire. For the woofer, the inductance parameters are 1 ohm and 1.44 mH. At high power, the loss of bass energy is guaranteed. Taking into account the parameters of the low-pass filter inductance, obtained by measurement, I ordered inductances for low-frequency and capacitance for high-frequency links of a higher class.
Total:
The work done made it possible to adapt the parameters of the resonant channel to the selected speaker and ensured the sound of the speakers was not lower than the expectations drawn by consciousness. I'll write about the sound below. All work took about five months (weekends and evenings, taking into account the presence of a fuse, time for listening and analysis, for the following calculations, etc.) and required certain costs. I can confidently say that the sound level corresponds to the acoustics of the price range from two million rubles. Actual costs, especially considering the existing equipment, are disproportionately lower. The path traveled was not easy. The created speaker sounded not only thanks to the accurate or successful calculation of the resonant channel, intuitively, to some extent, the chosen speaker, its approach to modeling and manufacturing the cabinet. Let me remind you that the built speaker system is two-way, the presence of a crossover is mandatory. Working with the crossover also allowed me to contribute to the final sound and gain a rewarding experience. Damping was not used in the speaker design. Perhaps I will try to evaluate the effect of damping in a particular case. I can say that the accumulated experience made it possible to evaluate the two variants of speakers for the 75GDSh3-1 speakers mentioned at the beginning, to see the shortcomings of the bass tuning and make adjustments.
There is no ready-made front speaker option for the 15XA38Nd speaker yet. There is a project. A new calculation of speakers with a 75GDSH3-1 speaker with increased bass response has been performed. The new variant will be equipped with a tweeter. Given the current workload and the delivery of additionally ordered components, these projects will be implemented no earlier than October-November of this year. The results will be presented. Part of the speaker cabinet design for the 15XA38Nd head is shown below:
Sound
It is possible that I have developed sentimentality. The achieved sound of two-way speakers on one or the other tracks led to spiritual and heart trembling, to blocking the breath, provoked to re-listening to favorite compositions. Right or wrong sound - I do not discuss. If the sounding speaker evokes in the listener the conviction of reality from the audible music, vocals, sounds and overtones, the goal has already been achieved. If individual turns of the musical program can dry the throat, make the eyes moist - the task is completed to the maximum. I am inclined to believe that the built prototypes of future speakers are close to the coveted maximum.
To be frank, without such a result, I would not allow myself to openly share my achievements. Perhaps, someone will say, beginners are lucky. I got double luck. Two pairs of magnificent speakers based on 75GDSH3-1 speakers, released in the Soviet era, which have carried out 35 years of stage life and a pair of new ones, based on 15XA38Nd speakers from the Spanish Beyma. Let it be lucky, but for those who consider it possible to make such speakers, given the additional recommendations provided in the material, the result is guaranteed. It is for such people that I write.
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Do-it-yourself shelf acoustics
DIY or DIY
One day I decided to assemble high-quality acoustics for sounding a 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 the floor version, then 3 stripes 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. The idea to assemble “shelf speakers” with my own hands came a long time ago, and I threw the bait in advance to my good friend, the “sick” sound, with whom 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 case 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. There is no such thing as too much rigidity.
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 not bad in appearance, but purely constructively cause difficulties. As a result, it was decided to trim the side walls with ash veneer, and cover the remaining 4 walls around the circumference with leather, or rather 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 with a manual circular saw, and small pieces with 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 have already said that the ideal speaker system is single-way. 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 by a 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. The back wall is 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 the ideal option for a 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, a large number of factors influence the final result:
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. A 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 lot of software for calculating the parameters of cases. 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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Unfortunately, not every one of us can afford to have a high-quality speaker system in the house. Now even the cheapest option will cost at least 10 thousand rubles. However, do not buy low-quality speakers that make a squeaking sound? If you are so eager to have your own in the house, you can make it yourself.
Moreover, all suitable parts and elements can be purchased almost anywhere, and their cost will certainly not be 10 thousand rubles. How to do it yourself? You will learn about this from our today's article.
Instrument preparation
So, in the course of work, we need the following materials and tools:
- screwdriver;
- chipboard sheet or MDF (for the manufacture of the speaker cabinet);
- marker;
- jigsaw;
- 400 W PC power supply;
- radio tape recorder;
- Bulgarian;
- a pair of acoustic speakers;
- furniture screws and self-tapping screws;
- sealant (best used based on silicone);
- voltmeter and glue.
Before assembling, first of all, check the operation of the radio and find out whether it can be powered or not. It is also necessary to test the speakers for sound quality. After that, you can safely proceed to the manufacture of the case and other elements of the acoustic system.
Case manufacturing
As the walls for the column, you can use a regular sheet of MDF or chipboard. In this case, it is unacceptable to use plywood, since according to its characteristics it is very flexible and emits a strong resonance. When making the speaker cabinet, also consider the fact that the more air that remains inside the box, the softer the bass will be. Therefore, leave as much free space as possible, but everything should be in moderation (otherwise such speakers simply cannot be transported).
Place the shelf so that the speakers fall maximum amount air. Next, mark the places for cutting with a marker. Now you can safely cut a chipboard sheet with an electric jigsaw. Note also that the edges of the cut parts of the tree should be carefully aligned. To do this, use a small construction grinder. Please note that it can work with several discs - for metal and for wood. We need the latter option, since when processing such materials, the cutting element of the first type is simply erased and even smokes. Experts recommend using a petal circle.
Now the matter is small. On the case, mark the places for screwing furniture screws and use a screwdriver to tighten them to the end. In the case of screws, first make a mark under them and drill through holes. That's it, the enclosure for the speaker system has been successfully manufactured.
Wall fasteners
Emphasis should be placed on the strength of the wall fasteners. Do not save on screws and self-tapping screws. The design of the cabinet for the speakers should be as strong and durable as possible. If the number of screws is insufficient, under heavy load, the walls of the system will rattle a lot, thereby only worsening the sound quality.
Solid Assembly
How is a three-lane do-it-yourself made? After you have made the case (the so-called "monoblock"), you can proceed to a thorough assembly of the structure. Here it is best to apply cordless screwdriver with 4 mm hexagon for driving screws. Remember that inside the speaker its own sound load is distributed from minimum to maximum - the bottom wall, top, front and side.
How is it done by hand? At the next stage, the joints should be treated with silicone sealant. This is necessary in order to prevent the penetration of excess from the case out through the slots. Thus, the level of music playback will become even better. How is the speaker system made with your own hands? After lubricating all the slots with sealant, you will need to install the speakers and radio. The latter is best purchased assembled. The speakers, together with the radio, are installed through the holes made in the bottom wall of the monoblock.
When everything is ready, the final design should look like this: a power supply is located on the back of the monoblock, two speakers are on the sides (each of them is located in a separate column) and in the middle there is a car radio. Do-it-yourself speaker systems are made in a certain order of actions - first the power supply is mounted, and then the radio tape recorder. So it will be much more convenient for you to screw fasteners. But at this stage, the PC has not yet been finally assembled. Next, you will need to reinforce the stiffness of the corners. We will tell you about this in the next section.
How to make a speaker system with your own hands? Strengthening corners
The whole essence of the work lies in gluing certain parts of the monoblock with the subsequent installation of square or triangular glazing beads on them. It is not necessary to use "Moment" as an adhesive. With this case, the usual "PVA" will quite cope. Before applying the adhesive to the surface of the material, make sure that it is dry and the surface is not cracked or bent.
What needs to be done in order for the power supply to work?
To do this, you will need to put a jumper on the wide, large connector (in other words, short it). Here it is enough to use a regular paper clip. It connects two wires (green to black) and check the operation of the device with a voltmeter.
In order for these elements to have greater conductivity, after installing the contact, carefully solder their junctions. Now shove the block body inside the monoblock and attach it with self-tapping screws. Seal all gaps with sealant.
About soundproof material
At the next stage, a do-it-yourself speaker system is filled with a special sound-permeable material (here you can use a regular synthetic winterizer). They need to fill the entire volume of the columns.
In this case, you can not apply it to the diaphragm. This sound-permeable material significantly reduces the load on the walls of the system and reduces the speed of sound waves. So, when playing a melody, the speaker design will practically not vibrate. However, you should not follow the principle "the more the better." If you overfill the column with padding polyester, it may lose bass, and, accordingly, the sound quality will deteriorate significantly.
Fan
If your TV or computer speaker system is designed for high playback power, consider additional cooling elements.
After all, under high load, the elements of the speakers are very hot, which can cause their premature failure. And you need to install the fan in such a way that it blows from the inside out, that is, the hot air is taken out to the street (or room). If the heat from the radio is removed, overheating of the system parts will be excluded, and your speakers will last a very long time. At this stage, the question of how to make a three-way speaker system with your own hands can be considered closed.
- Speaker or speaker?
- Acoustics and electronics
- What is hifi
- Speakers
- Acoustics
Making loudspeakers with your own hands - this is where many begin their passion for a difficult, 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, the individual tuning of each plug for a specific instance of the speakers, firstly, does not affect 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:
- 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;
- 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 region of the crossover frequency will turn out to be significantly uneven and overtones will appear in the sound;
- 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 at direct current, and the impedance at the crossover frequency will be greater. 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;
- The impedance of the LF-MF link (GG, heads) is taken as the characteristic impedance? n of the low-pass filter (LPF), and the impedance of the HF head is taken as the characteristic impedance 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;
- 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;
- 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 almost 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.
- 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.
- Structurally and technologically much more complicated, see fig. below.
- 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.
- 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.
- 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.
- Gives overtones more than any other type of acoustic design.
- The test is carried out in a quiet room, in which you yourself must first stay in silence for half an hour;
- 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;
- The knuckle of a bent finger knocks approx. 10 cm from any of the prisms;
- Repeat tapping exactly in the center of the board.
When joining electroacoustics, you need to know the following about how speakers are arranged and work in acoustic systems. 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.
diffuser diameter larger diameter coils, and in diffuser GGs, he 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) significantly depend 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
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 waves: 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 movement 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 some kind of air bag. 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 cone material of almost all good speakers, it 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, as American radio amateurs called the small-sized GG low power with a very thin and light diffuser, firstly, for a high return - 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:
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 chamber separation 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):
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:
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, cover, front and back wall, partitions, 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:
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:
Video: do-it-yourself simple laminate speaker for your phone
spikes
Floorstanding and desktop speakers are installed on special legs - acoustic spikes - which exclude the exchange of vibrations between the speakers and the floor or table top. Acoustic spikes are on sale, but the prices - you know, a special product. So, weights for building and carpentry plumb lines have exactly the same configuration (cylinder turning into a cone with a rounded nose) and material properties. Price - you know. Feel free to put any speakers on spikes made of weights for plumb lines, they will cope with an unusual task for them perfectly.
