Homemade wooden column construction. Do-it-yourself speaker system: the choice of speakers, acoustic design, manufacturing

Recently, an article about a homemade tube amplifier was published in the Homemade World, today it’s turn to tell you how to make acoustics for a tube amplifier with your own hands.

Want cool acoustics? Not prestigious, from well-known companies, but just a cool one, giving out detailed, deep, atmospheric and quite energetic sound? If you do not live in a castle and do not plan to sound the stadium or try to impress your neighbors three floors below, but want to enjoy music, perhaps my acoustic recipe is for you.

There are things that I really want to do, but the lack of funds, materials, equipment, etc. stops me. But I really want ... I gave myself a pendel, and I got it ... By the principle: "I want it because I like it!" and because we must finally make acoustics for mine. I wanted to build a speaker that sounds good in both large and small rooms, and at the same time elegant, and not cabinet-like. All the same - an element of the interior. In any case, it should be a floor-standing speaker, since "shelf speakers" still need to be placed on stands.

Creation

For the tube one-cycle dynamics, I also chose "tube" speakers: 4GD-35 (4GD-36) and 3GDV-1 (2GD-36), widely known from Soviet radio.

3GDV-1(passport data):

Frequency range: 3150 - 20,000 Hz;
Frequency response: 14 dB;
Sensitivity: 90dB;
Working power: 2W;
Harmonic coefficient in the frequency range 4000 - 10000 Hz: 3%;
Resistance: 8 ohm;
Passport power: 3 W;
Long-term power: 3W;
Short-term power: 6 W;
Main resonance frequency: 1200 - 2000 Hz;
Weight: 0.11 kg.

4GD-35 (4GD-36)(passport data):

Frequency range: 63 - 12500 Hz;
Frequency response: 16 dB;
Sensitivity: 92dB;
Working power: 0.8W;
Harmonic distortion at operating power: 125 Hz: 7%, 200 - 300 Hz: 5%, 1000 - 8000 Hz: 3%;
Resistance: 4 ohm;
Passport and long-term power: 8 W;
Short-term power: 15 W;
Full Q factor: 1.4 (± 0.3);
Main resonance frequency: 65 Hz (+20, -15);
Dimensions: Ø 200 x 75.6 mm .;
Weight: 0.88 kg.

According to my comparative measurements, it turned out that 4GD-36 and 4GD-35 have the same frequency response, but 4GD-36 sounded more comfortable for hearing.

Four design options were considered:

Open box. Semi-open drawer.
Closed box. A box with a cat-hole.
TQWP - (TaperedQuarter-WavePipe - Expanding Quarter Wave Pipe).
Quarter-wave resonator (TwinPipe) in the image of Castle Knight 5, from the British Castle Acoustics.

All variants are noteworthy and have shown certain advantages and disadvantages in sound, although officially these speakers are intended for open design.

After sawing and breaking a bunch of boards, I share the results.

Open box. Classic light sound. Many people may like it, but reflections from the walls do not allow for a clear scene. If the body is closed at the back with a piece of felt (about 1 cm thick), then the situation is somewhat improved. This design (called: aperiodic loading) showed the best linearity, but at the same time more modest dynamic performance and sensitivity. The construction of the stage was also not impressive. Everything is very academically correct, but dry. The room has 10 sq. m you can still listen, but at twenty meters it became boring - a weak attack.

A box with a sound port on the front. Simple and quite effective. Niza stick out, the rest is in the norms of decency. Sensitivity and dynamics are average. For a room of 20 meters may be suitable, but at 10 meters "rowdy".

Since I wanted something with a twist, I settled on the option "from the knight's castle." In fact, the Twin Pipe has demonstrated the greatest sensitivity and better bass management than the popular TQWP. The sound is light, aggressive and open. The bass is adequate in both small and large rooms. The scene and the detail are pleasing. The linearity, however, this "mustang" is not at all high-quality: 18db (relative measurement in the resonating room), with a certain resonator setting, you can lower it to 14db. The only significant drawback is that the sound is like a "box". The sound port on the front panel is to blame for this. It is possible to deal with this by densely damping the case with various materials, but the sensitivity drops and then the meaning of choosing such a design is lost.

In general, all sound ports and bass reflexes are used to output any uterine sounds outside, so if you do not want to listen to how your gut sounds, it is better not to use them.

On the album "Bad Dream" Ronnie Dio has such a song - "All the fools swam far away." This is apparently about me, and now I am proud of it.

So what am I inventing? A bike with square wheels ... based on a speaker for an open design ... The problem is that for a good attack the acoustics need a back wall. Take 10GDSH-1-4 and such questions would not arise at all. Put it in a box, or in a big box with a fazik, put it - it will "sing". But I have already “swam far away”. The case for 4GD-36 is ready, and this is ZYa!

Test and listen ... ???

Regardless of the style of music, the sound is aggressive and harsh, like a heavy metal concert. Drums and guitars punch walls and ears. Having enjoyed this "joy", I wanted to return to musicality.

Where to "sail" now? I return to the aperiodic load, but now with the addition of padding polyester. I lay the fluffed synthetic winterizer in a wave, and I close the back of the speaker with a felt of 5 mm thick.

Here it is! The musical sound I need is received. Light open sound, not traumatic for the ear, but with sufficient dynamics. Even Le Binks' drum introduction to Judas Priest Better by you, better than me sounds convincing in concert. Arranging "deep" listening ... Three months have passed ...

Conclusion

First, about the bad. Acoustics and my one-beat are not at all "friendly" with modern compressed music and musical styles of increased density and assertiveness, whether it be electronics or thrash metal and the like. At the exit, creaking porridge.

Good. Classic heavy metal plays well (but not overwhelming). Hard rock is not bad. Led Zeppelin and early rock in general sound very organic, until 1976 (apparently old recording technologies let you know). Electronics: Kraftwerk, Yello, Enigma, Era, B-Tribe.

About the magnificent. Antonio Vivaldi and violin classics in general. Chamber jazz, such as Diana Krol and the like. All vocals of all the singers are perfectly reproduced by the combination of Magnifique Evolution & Magnifique Accustic. With a claim to luxury!

Recipe and ingredients

The body is made of laminated chipboard 16mm thick. Internal fixing: slats, screws, glue. I did not additionally thicken the walls (except for the lower part of the front panel), citing the fact that the acoustics are low-power.

Internal casing damping: felt, synthetic winterizer.

It is necessary to put a seal under the speakers or "put" them on the plasticine.

Base: Particleboard with a decorative aluminum corner around the perimeter.

Adjustable legs, based on crab furniture nuts.

Filter - capacitor MBGSCH-2 4mkf 160v.

The speaker connections are in phase.

Internal wires copper 1.5 mm "Odeskabel".

Connectors for "banana" Soviet instrument (chiseled bronze contact in a carbolite case).

Amplifier-AC cable: Odeskabel 2X4mm; Banana Profigold connectors.

Total: $ 72.

After assembling the case, securing and connecting the speakers, place the speakers in the position you want in the room. Listen to your favorite music at the volume you are interested in. Add felt and synthetic winterizer "to taste", achieving the desired tone in the sound.

Thank you for your attention and wish you success.

Application

Reasoning about

There is a widespread belief in the network that it is possible to design speakers only if you have in your arsenal a professional measuring microphone, or even better, a sound level meter (for example: VShV-003) and a thoroughly damped, muffled room, without resonances. Next, you need to thoroughly study the work of design and simulation programs. And already on their basis, from special audiophile materials to make a truly "correct speaker".

All of this is partly true. Partly ... More precisely, not quite, really. That is, in real life, it will not be so.

Even if a VShV-003 or its analog is lying around in your closet, the measured frequency response, in a city apartment, will be replete with resonant distortions that cancel out all the potential accuracy of the measuring equipment. For the same reason, one should not "hunt" for any special microphones, such as the Panasonic WM-61A.

Speaker cabinet design programs, of course, help you navigate, but purely virtually.

The main thing is the concept and the desire to implement it on the basis of common sense and proportionality. A live experiment will always show what is better and what sounds worse in a specific setting, for which the speaker is created. For example: a speaker needs air - this is a fact, so you shouldn't squeeze it into a tight, closed box, but you shouldn't put it in a huge wardrobe either. Its installation dimensions already indicate the minimum proportions of the speaker cabinet in width, and in depth and height, statistically, it is twice as large. The height of the speaker from the floor affects the transparency and density of the lows and is determined only empirically in a specific setting, and not by sophisticated programs that are closed on themselves.

Even more creativity involves the process of damping the case with different materials (felt, linoleum, cotton wool, synthetic winterizer, etc.). Having done everything right, on the recommendation of dealing with resonances, you can completely kill the music in the sound.

The damping factor and impulse response of your amplifier will make your designed speaker work just the way they want, breaking all the rules and canons. The conclusion is to experiment, listen and correlate with relative measurements. These measurements can be safely done using a simple measurement microphone assembled from a cheap Chinese microphone and any line amplifier on a single microcircuit. Then connect it, at least to a sound card, or in the old-fashioned way "hum" with a generator and a millivoltmeter.

I made my measuring microphone based on a Chinese with an insignificant name JM901, and a linear amplifier on K157UD2. I collected it 15 years ago, just for fun, and put it in the closet. Now, all of a sudden, he came in handy and did an excellent job with his task.

See also:

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

More details about how the dynamic head works HERE.
The methods of breaking the acoustic circuit are called acoustic design, and each of them is designed to impede the penetration of air from one side of the diffuser to the other.
There are several main options for breaking an acoustic short circuit. The easiest is to use sheet material in the middle of which a hole for the dynamic head is cut. This is called an acoustic screen:

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

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

The next option for acoustic design is a box with a bass reflex:

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

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

An even greater return at the resonant frequency can be obtained with a horn version:

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

This option differs from all the previous ones primarily in that it emits only at the resonance frequency and requires the strictest adherence to the calculated dimensions.
The last three options are mainly designed for the use of a low-frequency dynamic head, and the previous ones are quite suitable for a wideband speaker. Therefore, if the speaker system has other speakers in addition to woofers, for example, midrange and treble, then it is not recommended to embed them in a housing with a woofer.
In any case, to calculate the dimensions of the speaker, you need the characteristics of the dynamic head, in particular the Thiel-Small parameters. If these data are not available, but before you start calculating the dimensions of the speaker case, you need to get them. There are a lot of descriptions of methods for obtaining these parameters - it is enough to use any search engine.
Of course, these are not all types of acoustic design - these are the most popular.
The dimensions of the enclosure are calculated using special programs for calculating the speaker enclosures. Finding them on the Internet, as well as instructions on how to use them, is also not problematic.
When designing the speaker system, some technological features should be taken into account - if the front panel on which the speaker is installed is recessed into the housing, then additional ribs will need to be made, into which the front panel will actually rest:

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

All this will give the front panel an additional, more rigid connection with the case.
Also, you should not forget about the methods of attaching the dynamic head to the front panel and the pitfalls that you may encounter. Mounting the speaker from the outside is most preferable, since it does not mechanically weaken the structure, however, this method involves chamfering along the diameter of the dynamic head and immersing the speaker inside the case so that ALL radiators, both LF, MF, and HF are on the same line. chamfering reduces the mechanical strength of the bezel and requires an additional inner ring to restore it. The relevance of this ring is the higher, the more power is expected to be obtained from the manufactured speaker and at powers above 150 W it is already 100% necessary:

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

To solve the problems of tightness, you can use a door seal - self-adhesive strips of porous rubber, sold in all hardware stores. The seal is glued along the perimeter of the chamfer and during the installation of the speaker completely fills all the gaps:

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

It is advisable to use natural material for the manufacture of speaker cabinets, plywood is optimal, but this material is too expensive. Therefore, it is better to use plywood for the construction of loudspeakers of the middle and high price category, using VERY good quality drivers and a power above 100 watts.
For a medium price category and small capacities (up to 50W), you can use fiberboard or MDF (the same as fiberboard, only the thickness and density is greater), but it must be processed and modified, or chipboard.

For powers up to 10 W, plastic is also quite suitable, but also with the use of technological tricks.
The first problem, in the manufacture of speakers from plastic, arises when the bounce of the plastic itself is eliminated, especially manifested in the centers of the sidewalls. You can get rid of this unpleasant sound by using thicker plastic, or you can glue additional stiffeners. If the plastic dissolves with dichlorite, then dichlorite can be used to fix the ribs, with plastic chips dissolved in it. If the plastic does not dissolve with dichloromethane, then it is better to use epoxy glue, preferably Dzerzhinsky production. Before gluing, the places of the context should be carefully processed with a grain of sandpaper and are not afraid that the glue forms rollers at the point of contact of the parts to be glued:

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

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

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

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

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

The speaker can be assembled using self-tapping screws, but since the power is not more, you can also glue it with epoxy glue or PVA, only it is better to buy it not in a stationery store, but in a household or construction store. This PVA will be called MOMENT-STOLYAR, water-dispersible glue. Buy in the market recommended only in summer - after freezing, the glue seriously loses its quality. However, to calm your conscience, it is better to screw at least a couple of self-tapping screws into each bar.
In the manufacture of speakers, they sometimes make a gross mistake - the midrange-high frequency link is not acoustically protected from the impact of the rear side of the woofer diffuser, which leads to a decrease in the efficiency of the speaker itself, and often to the failure of the midrange link - too strong air strikes from the rear side of the woofer diffuser lead to pushing the midrange speaker coil out of the magnetic gap and the coil jamming.
Much more often they forget to subtract the volume of the protective casing of the midrange-tweeters from the total volume of the speakers, as a result, the internal volume of the speakers is less than necessary and the final characteristics are heavily lubricated - the resonant frequency of the phase inverters increases noticeably, which will lead to unwanted overtones.
When assembling speakers with a power of up to 100 W, you can also use either chipboard or 18 mm plywood, although of course it is better to look for a 22 mm thick material. To exclude the occurrence of resonances in the sides of the speaker cabinet, additional bars are also used through which parts of the speaker are attached. It will not be superfluous to install a "cross" and an additional washer for attaching the woofer of the dynamic head, as well as processing the speaker from the inside with sound-absorbing materials, for example, pasting with paralon or foam with a thickness of 5-10 mm, just do not forget that pasting will "eat" part of the internal volume and it must be corrected for when calculating the size of the case.

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

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

It should be noted here that the use of a large number of speakers, including for dividing the audio range, begins to introduce some troubles - it is rather difficult to achieve signal phasing in those places where the frequency response of the speakers neighboring in the range intersects. Therefore, you should not chase a large number of stripes for a homemade speaker - this porridge with such oil can be very spoiled.
Speakers with a power of 100 to 300 W are best made of plywood, and you will have to look for plywood 22 mm thick. The speaker is also assembled using stiffening bars that are glued. It is better to give the bars the shape of equilateral triangles, where the legs will be attached to the sides, and the hypotenuse will be directed towards the inside of the body.
If it is not possible to find plywood of this thickness, then you can use plywood with a thickness of 8 mm glued three times - the final thickness of the material is 24 ... 25 mm. The adhesives are listed above.
As a technological advice, one can only recommend that you first cut the necessary blanks and only then glue them together, and immediately tighten them with self-tapping screws.
When installing a "cross" inside the speaker, which will not be superfluous, it is better to round the corners of the staggering beams - rather large volumes of air are already moving and turbulence may occur around the right angles of the screeds. It is also recommended to "round off" all internal corners, using plasticine or applying several layers of thick anti-gravel.
Another type of acoustic design is separate enclosures for each speaker. These speakers do not use passive filters, and the signal is divided into ranges immediately after the amplifier volume control. Then the split signal is fed to three separate power amplifiers, which actually work each for its own speaker:

It would not be fair not to mention the "fillers" often used in speakers - small rollers of sound-absorbing material lying inside the speaker. Such rollers make it possible to slightly increase the calculated internal volume of the body, however, in order to correctly manufacture such a "filler", it is necessary to know its acoustic properties. It is rather problematic to obtain the characteristics of the "filler" in household conditions, so it remains either to refuse to use the "filler", or to experimentally find out the required volume and material used (usually fluff cotton wool, batting, centipon).
At powers of 100 W or more, it also becomes important to ensure the stability of the speaker case, since quite a lot of work is already being done to move the diffuser and the air is actively "resisting". It is also desirable to break the mechanical connection between the bottom of the speaker and the floor on which the speaker is installed. For these purposes, they usually use either tripods, which are problematic to make at home, or use steel spikes screwed into the bottom of the speaker:

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

For powers closer to 1000 W, the thickness of the material should already be quite large, for example, two layers of 18 mm plywood plus a layer of 18 mm DPS for a total of 54 mm, and DPS is glued between the plywood layers, however, more specifically, the speakers are already moving into the category "for sounding", therefore quality can be sacrificed for mobility. Based on this, it is possible to use double 18 mm plywood with a "cross" installed inside.
It is not difficult to notice that with an increase in power, the wall thickness of the speaker increases. This is primarily due to the fact that it is necessary to isolate the air moving inside the speaker from the listener. Keep in mind, however, that the speaker cabinet can also resonate. It is to eliminate this nuisance that it is better to use the internal pasting of the enclosures and to minimize the overtones obtained from the resonance. It is not difficult to check the resonant frequency of the case yourself. To do this, you need to tilt the speaker by 20 ... 25 degrees and throw a rubber mallet on top of it from above, pull out the handle first. The tilt of the speaker is necessary so that the blow is single and the mallet bounces far to the side.
A microphone attached to the speaker (membrane hole to the body) and connected to any linear amplifier on the oscilloscope screen will draw both the moment of impact and the after-sound that the body itself gives. The test is, of course, rather rough, since in reality the "shock wave" comes from the inside, and during the experiment from the outside, nevertheless, on the basis of the results of this test, one can judge at what frequency the case itself resonates and how quickly the attenuation occurs:

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

The finishing of the speaker system can be very different, there are no strict requirements here. If the body is made of plywood and the drawing is pretty pretty, then the body can be sewn up, and then several times covered with colorless varnish:

You can buy veneer of valuable species of trees and paste over the speaker with veneer to match the color of the furniture in the room:

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

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

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

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

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

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A characteristic feature of counter-opening is that the sound coming to the listener from virtually all directions, although it creates an impressive effect of presence, cannot fully convey information about the sound stage. Hence the stories of listeners about the feeling of a piano flying around the room and other wonders of virtual spaces.

Counterperture

Pros: A wide area of effective surround perception, naturalistic timbres due to the non-trivial use of wave acoustic effects.

Minuses: The acoustic space is noticeably different from the sound stage conceived when recording a phonogram.

Other...

If you think that this list of design options for speakers is exhausted, then you grossly underestimate the design enthusiasm of electroacoustics. I described only the most popular solutions, leaving behind the scenes a close relative of the labyrinth - a transmission line, a band resonator, a case with an acoustic impedance panel, load pipes ...

Bowers & Wilkins' Nautilus is one of the most unusual, expensive and reputable speakers around. Design type - load pipes

Such exoticism is quite rare, but sometimes it materializes in a construction with a truly unique sound. And sometimes not. The main thing is not to forget that masterpieces, like mediocrity, are found in all designs, no matter what the ideologists of a particular brand may say.

A loudspeaker is a very modest speaker system that has one or more loudspeakers with a built-in amplifier. Speakers are used to increase the sound volume, and the sound is boosted using the speakers. The speakers are made up of two magnets: usually a ceramic permanent magnet and an electric magnet, which is controlled by an audio amplifier. Thanks to these magnets, sound is generated when they interact. Loudspeakers are divided into two more categories: passive - that is, in which there is no built-in audio amplifier, for example, headphones; and active - respectively, speakers, which have their own built-in audio amplifier. The active speaker system has its own power supply. In this article, you will see how to make a homemade active speaker system with your own hands. This speaker can be connected to a computer, a phone, a player, and so on. To make this homemade product, I needed:

Materials:
1) Two speakers with a power of 3 watts each (they will serve as a sound source);
2) Three and a half millimeter plug for connecting the speaker to various devices;
3) (the amplifier will receive sound signals from some device and transmit them to the speakers, amplifying these signals);
4) Switch to turn off the power of the speaker;
5) Wires for connecting contacts;
6) Insulating tape for insulation of wires and other needs;
7) USB plug for connecting to power supply;
8) Heat shrink tubing for insulating exposed contacts;
9) Plywood (the body will be made of plywood, since this is the most affordable material);
10) Self-tapping screws for housing assembly.

Instruments:
1) Electric soldering iron for soldering wires;
2) Glue gun and hot melt glue for gluing some parts and for insulating contacts;
3) Stationery knife for cleaning wires from insulation and for other needs;
4) Heat shrink tube lighter;
5) A hacksaw for cutting plywood;
6) Jigsaw for sawing round and other holes on plywood;
7) Electric drill for drilling holes;
8) Screwdriver for tightening self-tapping screws;
9) Ruler and pencil for drawing marks on plywood for the column case;
10) Sandpaper for grinding the body;
11) Nippers for cutting wires and extra contacts;
12) Compass for drawing circles.

The process of making a homemade active speaker.

Let's prepare two three cotton loudspeakers, a 3.5 mm jack and a PAM 8403 audio amplifier and connect their pins using jumper wires.

The characteristics of the speakers are recorded on the back of them, namely, here they are:

The 3.5mm jack has three pins: left channel, right channel, and common. There are four more pin plugs: left and right channels, common and microphone; but this column does not have a microphone and why, so you can not use the four-pin plug. The pin connections are shown in the photo.

We will use an audio amplifier ordered from Aliexpress of very good quality as mentioned earlier. This amplifier is powered by a voltage of five volts, so the future speaker can be connected to both a laptop and a phone charger ...

We will also use the power button to turn off the speaker.

We take the wires and strip their ends from insulation using a clerical press for future soldering.

We solder these wires to the audio amplifier using an electric soldering iron, but very carefully so as not to spoil or damage the amplifier.

In my case, the blue wire is a plus and the brown wire is a minus.

We cut off the excess protruding contacts with pliers in order to look neater.

We fix the wires to each other with insulating tape.

It should look like this, as shown in the photo.

Now we solder the power cable to the amplifier with a USB plug. Yes, at the end of the article, the wire will be white, since I soldered it due to insufficient length, so don't judge too much.

We clean the USB wires and solder one of the wires with an electric soldering iron to the speaker's power switch.

We insulate the wiring using heat shrink.

Now we solder the resulting two wires to the audio amplifier, be sure to observe the polarity: in my case, brown is a minus, blue is a plus.

Again, bite off the excess on the board with pliers.

That's what I did:

Now we solder a wire with a 3.5 mm plug to the audio amplifier.

The wire should have at least three contacts, but exactly three is better.

We strip the wires and solder them to the 3.5mm plug.

Now we solder the wires to the audio amplifier, but each wire is in its place.

We solder them to the board according to the wire colors, namely the black wire is the left channel, which is marked on the board with the letter L; the red wire is the right channel, which is marked on the amplifier with the Latin letter R; and the green wire is the common channel, which is marked on the amplifier, respectively, by the Latin letter G.

Now we insulate the 3.5 mm plug with heat shrink and hot melt glue.

In general, I got it like in the photo.

Now a more complex process begins, namely the blanking of the case.

On plywood, drawing a rectangle, when dividing it in half, we get two identical squares, in each of which we draw circles of equal diameter in the center of the squares using a compass for future speaker seats.

Using an electric drill, we drill a hole to thread the jigsaw into this hole.

We cut out a rectangle with a hacksaw.

Using a hand jigsaw, cut out the circles from the rectangular part of the column case.

Three watt speakers can be easily inserted into the resulting two holes.

And two more rectangular pieces of the same size.

So far, from all that we have received, we are assembling the body.

Now you need to attach the audio amplifier to the front of the case.

To do this, we drill a hole with an electric drill, it is necessary that the amplifier is freely and reliably installed in this hole.

From the inside of the part near the drilled hole, using a clerical knife, we dig out a recess for the amplifier board.

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

My brother and I had the idea to create something unusual, which no one else would have, for a long time. Love for true music left no doubt that these would be hand-made acoustic systems. While studying at the university, there were even trial versions in the form of two-way "poles" based on speakers from and a Chinese "tweeter". Then invaluable experience in working with wood was gained, an understanding of what could be done and what would have to tinker arose, there was a need to buy a tool. We are well aware of the importance of careful calculation of all acoustic parameters and sound settings. At that moment we could not afford any of this, so the implementation of our plans was postponed indefinitely ...

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

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

1. Prevent the generation of standing waves inside the speaker.

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

To ensure the first condition, the back panel was made narrow, the absence of parallel surfaces also contributes to this, and at the same time creates the effect of "infinite space". But the column needs volume, so the front panel is wide enough. Most firms try to make the speaker as narrow as possible, but acoustics with a wide front panel sound more.

To provide the second condition - the panel was broken at angles of 7.5 and 15 degrees to the radiation plane
speakers. Concave side surfaces, not a single perpendicular plane both in relation to each other and to the front of wave propagation, all this serves the same purpose - to achieve, if not Hi-End, then at least good Hi-Fi. Two phase inverters are installed at the back, however, they serve not for resonant amplification of low frequencies, but for equalizing the pressure inside the speaker and tuned to other frequencies so that they do not "whistle" when air passes - they put two on each speaker. The cabinet is installed on four copper spikes, and the stand itself stands on three steel supports with plastic overlays, with the ability to adjust the height and angle of inclination, all this is done so that the vibration of the speakers is not transmitted to the supporting surface. Seen from above, the AC resembles a Soviet mouthpiece. Bulkheads are installed inside for rigidity and giving the side surfaces the desired bending radius. The edges of the front and rear panels have been rounded off. It was also planned to glue the sides with veneer for aesthetics.

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

Two sheets of plywood with a thickness of 18 mm and 9 meters of a bar of 95 × 35 mm were purchased. The plywood was lined, cut into the required parts. Straight lines were cut with a circular saw according to the rule, and curved lines were cut with a milling cutter (along the way, a compass was made for a milling cutter with the ability to set a radius from 300 to 1500 mm). I'll make a reservation right away: cutting 18 mm plywood with a router is a bad idea, it is better to cut the workpiece with an electric jigsaw with an indentation of 2-3 mm and finish the shape with a router, the surface will be cleaner. The intricate details were printed on a Whatman paper at a 1: 1 scale and made something like templates. For manufacturing details took about a month, unfortunately, this process was not photographed. After processing all the parts, they were assembled:

They collected everything with the help of corners, screws and wood glue.

In the photo above, the holes for the speakers, bass reflexes and speaker terminals have already been cut. To extinguish any possible resonances and overtones, it was decided to lay out the inner surfaces with batting: cut with a knife on paper, secured with a stapler. Immediately, in the lower cavity, they were installed.

After much abuse of 18 mm plywood, it was not possible to bend it to the required radius. Therefore, it was decided to select the thickness of the side panels from three thinner plywood layers. Each layer was screwed to the spacers with self-tapping screws and coated with wood glue to glue them together. The joints of all panels were lubricated with sealant from the inside. The gap between the panels in the photo is not shoddy build quality. The screws had to be loosened, otherwise the side panels would not fit. Top covers by rolling a bypass cutter directly over the column.

Final fitting and assembly of some elements:

After the main part of the bodies was assembled, they began to sand, putty, sand again ... and so on until smooth, even surfaces were obtained. It took us two jars of putty and a set of grinding wheels. There was a lot of dust.

After everything was sanded, they started pasting the columns with veneer. The main color of the speakers is gloss black, contrasting veneer patterns were intended to dilute this "blackness" and give a more aesthetic look. The experienced eye immediately recognizes the Jamo Epicon 8... The veneer was cut according to patterns from Whatman paper, with a knife on paper. If the veneer is thick (we had a thickness of 0.6 mm), then you do not need to try to cut it off at once to the full depth - it is large, so that it will burst.

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

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

After the glue has dried, the veneer can be sanded. On the left before grinding, on the right after. It doesn't look very nice right away, but after applying varnish or stain, everything changes.

In the absence of another room, they painted on the balcony. Before painting, the balcony was thoroughly washed and covered with cellophane to prevent dust from entering the painting area. The housings were “vacuumed” and wiped with a lint-free cloth (sold in auto dealerships). You do not need to wipe with a damp cloth - the veneer is very afraid of liquids, it begins to exfoliate. To prevent paint from getting on the veneer, it was covered with masking tape. Since the surfaces are large, it is better to glue the tape only along the edges, and fill the sheets of paper cut in shape under it.

Acrylic was chosen as the paint and applied.

The first layer will reveal all the imperfections in the wood (scratches, dimples, gaps) that were allowed during sanding. Everything that has manifested itself is cleaned, putty, polished.

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

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

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

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

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

We hammer the bass reflexes, you need to beat more carefully, we broke one after all, we had to buy it in addition b. We solder the acoustic terminals, put them on the sealant and screw them on.

We solder and install the speakers. It is worth noting that on the inner side of the speakers along the edge, we glued rubber tubes to prevent air from flowing through possible slots.

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

First audition... This was the most anticipated and exciting event - the result of four months of work. I will not say that the sound has reached the High-End level (although I do not even know how it should sound), but it did not disappoint either.

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

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

A few numbers:

The cost of the speakers is $ 400, of which $ 270 was spent on speakers and crossovers.
Maximum power 300 watts.
Impedance 4 ohms.
The total weight of one column is 38 kg.

Dimensions 1135 × 370 × 315mm

On my own behalf and on behalf of numerous fans of the site "Soundmania" I would like to express and wish great creative success to Fedor Gartsuev!

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

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