DIY sound speakers drawings. Homemade speaker system. For the frisky and the computer

At first glance, making your own speakers is quite simple. However, this is misleading. First of all, it should be noted that the models are made with different elements. Depending on them, the device parameters and sound quality will be different.

There are special requirements for computer speakers. You can also make a model for your car or studio yourself. In this case, it is very important to follow the instructions. First of all, to assemble the speakers, you should consider the standard model diagram.

Speaker layout

The speaker circuit includes drivers, pads, diffuser and crossover. Powerful models use a special bass reflex. Amplifiers can be installed with field-effect or switching transistors. To improve sound quality, capacitors are used. The woofer is matched with the amplifier. The dynamic head must be attached to the seal.

Single speaker models

Single speaker speakers are very common. To assemble the model, you will first have to deal with the body. Plywood is often used for this purpose. At the end of the work it will have to be sheathed. However, the first step is to make the side posts. For this purpose you will have to use a jigsaw. you can choose a small power.

The inside of the plywood must be stitched with vibration-proof tape. After fixing the speaker, the seal is fixed. Glue is used for this purpose. Next, all that remains is to attach the diffuser. Some people make a separate shelf for it and fix it with stacking screws. To connect the speaker to the plug, a terminal block is installed. How to turn on speakers? For this purpose, a cable is used from the terminal block, which should lead to a power source.

Model drawing for two speakers

Speakers with two speakers can be made for home or car. If we consider the first option, then a pulse type diffuser will be required. First of all, durable plywood is selected for assembly. The next step is to cut out the bottom post. Models with legs are very rare. To cover the veneer, you can use regular varnish. There is no need to glue vibration isolation tape to the front pillar. The diffuser is mounted under the speaker. To make a hole in the panel, you need to use a jigsaw. The bass reflex is fixed at the rear wall. Some manufacture devices with horizontal speakers. In this case, the diffuser will be located at the top of the structure. Speaker wires are of the two-core type.

Devices with three speakers

Speakers (homemade) with three speakers are very rare. These devices are most suitable for the multi-channel type. To assemble the model, first of all, sheets of plywood are selected. Some also recommend using veneers. However, models made of natural wood are quite expensive on the market. The speakers should be installed horizontally. The device will also require an amplifier.

Metal corners are used to secure it. To connect the plates you will need tightening screws. In some cases, the plates are secured with glue. Next, the model will have to be partially covered with leatherette. The next step is to install the terminal block. In order to fix it on the body, you will need to make a separate hole. It is also important to note with regulators. Microcircuits for them are used of the capacitor type. When the speakers produce noise, you need to change the diffuser.

Studio devices

Speaker drawings for studios assume the use of powerful speakers. The diffuser is most often used of the pulse type. Many experts recommend installing two amplifiers. For normal operation you will need a zener diode.

In order to assemble the speakers yourself, the housing is first made. Round holes are made on the front panel for the speakers. You will also need a separate output for the bass reflex. The design of the columns is quite different. Some people prefer to varnish the surface of the case. However, there are models covered in leather.

Models for computers

Speakers for computers are often made with one speaker. To assemble the model, veneer sheets of small thickness are selected. A hole for the speaker is cut out on the front panel. The bass reflex must be located at the rear of the housing. If we consider low-power models, the amplifier can be used without a resistor.

To adjust the speaker volume, special crossovers are used. These elements are allowed to be installed on a bass reflex. If we consider devices with a power of more than 100 W, then amplifiers can only be used with resistors. Some people select pulse diffusers for the model. At the end of the work, the terminal block is always installed.

Automotive modifications

Available with two or three speakers. To assemble the model yourself, you will need sheets of plywood. In some cases, varnished veneer is used. To fix the speaker, you need to make a hole in the panel. The next step is to install the bass reflex. Some modifications are made with low-frequency cores. If we consider speakers (homemade) of low power, then the bass reflex can be installed without an amplifier.

In this case, a multi-channel crossover is used to control sound. Some specialists install terminal blocks behind the bass reflex. If we consider speakers with a power of more than 50 W, then the microcircuits are used for two amplifiers. The diffuser is installed as a standard pulse type. Before fastening the case together, it is important to take care of the vibration-proofing layer. For the terminal block, you need to make a separate hole on the plate. Some people believe that the body must be cleaned. The wires for the speakers are of the two-wire type.

Open-back speakers

Portable speakers with an open case are quite easy to make. Most often they are made with one speaker. Holes are made on the back panel of the device with a drill. The plates are directly connected with tightening screws. The diffuser for such devices is suitable for pulse type. Bass reflex units are often installed with one amplifier. If we consider powerful portable speakers, they use a resistor crossover. It is attached to the bass reflex. Many experts recommend installing speakers on a seal.

Devices with closed housing

Speakers (homemade) with a closed housing are considered the most common. Many experts believe that they are the best in sound quality. Bass reflex devices for devices are suitable for the operational type. The woofers are installed in the holes. For the purpose of assembling the case, ordinary sheets of plywood are suitable. It is also important to note that there are modifications with cores. If we consider high-power speakers, the terminal blocks are installed in the lower part of the housing. The design of the models is quite different.

20 W models

Assembling 20V speakers is quite simple. First of all, experts recommend preparing six sheets of veneer. They should be varnished at the end of the work. It makes more sense to start assembly by installing the speakers. The bass reflex is used as a pulse type. In some cases it is installed on pads. Experts also recommend using rubber seals.

Power supply to the speakers is provided through the terminal block. It is attached to the back panel. The bass reflex can be installed either with or without an amplifier. If we consider the first option, then the cores are selected of the phase type. In this case, the woofer does not need to be used. If we consider speakers without an amplifier, then they use a crossover. At the end of the work, it is important to clean the body and varnish it.

50 W devices

Speakers (homemade) rated at 50 W are suitable for ordinary acoustic players. In this case, the body can be made from ordinary plywood. Many experts also recommend using natural wood veneer. However, it is important to note that he is afraid of high humidity.

After choosing the material, you should work on the speakers. They must be installed next to the bass reflex. In this case, you cannot do without an amplifier. Many experts recommend selecting only low-frequency crossovers. If we consider modifications with a regulator, then they use a pulse diffuser. The terminal block in this case is installed last. You can always use leatherette to decorate the speakers. A simpler option is to varnish the surface.

Speakers with a power of 100 W

100 W speakers are suitable for powerful ones. In this case, the bass reflex is taken only of the pulse type. It is also important to note that the amplifier is installed with a crossover. Many experts recommend using veneer to assemble the case. It is better to install the woofer on a pad.

Now on sale (at least in large cities) you can buy a wide variety of acoustic systems in terms of power, design, overall dimensions and cost for almost every taste, ranging from small-sized ones with a volume of 2...3 dm 3 to floor-standing ones with a volume of over a cubic meter. However, the vast majority of these systems have one unifying feature: they are all of the closed box type.

This means that the acoustic design is tightly closed and the speaker cone works like a piston, the cylinder of which has a constant volume of enclosed air inside.

The acoustic design of a closed box has a number of undeniable advantages, among which the most important are the following:

1. Acoustic short-circuiting between the front and rear sides of the speaker cone is completely eliminated, which increases the relative (but not absolute!) response at the extreme low frequencies and, therefore, reduces the overall unevenness of the frequency response due to this part of the spectrum
2. Due to the fact that the diffuser works like a piston in a closed cylinder, the resistance of the internal volume of air in the case increases sharply, which leads to a rapid attenuation of the free vibrations of the diffuser, and this is equivalent to an increase in the damping factor.
3. Thanks to the increase in low frequency radiation (see point 1), it is possible to significantly reduce the overall dimensions of the case while maintaining sound quality in the bass register.

However, as they say, only cheese in a mousetrap is free. Everything else has to be paid for. In the case of compression speaker systems, the cost is their efficiency and, therefore, the electrical power that must be supplied to the system to obtain sufficient sound volume.

Readers have probably noticed that most modern portable and compact receivers, radios, as well as their car twins, have a rated output power of 50, 60, 100 and even 300 W! Meanwhile, the vast majority of old tube radios and radios, even of the highest class, had an output power 10...20 times less. For example, the top-class console stereo radio “Symphony” had an output power of each channel that did not exceed 6 W, the first-class desktop receivers “Latvia”, “Mir” “T-689” had an output power of 5 W, although the volume of their sound was by no means less , but rather more than that of today's car radio with a nameplate power of 2x30 W.

What's the matter? But the fact is that before the widespread use of transistor radio equipment, not compression, but exclusively open emitters were used as acoustic systems, i.e. those in which the back side of the speaker diffusers communicated with the air volume of the room through the perforated rear wall of the case. And although such open speaker systems did not have the advantages of compression systems, they nevertheless provided excellent sound quality with significantly less electrical power input.

A comparison of the two types of speaker systems is provided so that the radio amateur can make the right choice. The fact is that today’s range of high-power final transistors makes it possible to obtain undistorted output power of 50 and 100 W with exceptionally high efficiency, since special circuit solutions allow these transistors to operate in class B with virtually no noticeable nonlinear distortions. In this case, the use of compression acoustic systems is not only possible, but also completely justified.

The situation is different with tube amplifiers. Modern tube final stages can only operate in pure class A.

This is necessary to ensure an acceptable level of nonlinear distortion factor. But this, as you know, is the most uneconomical mode. In addition, powerful final lamps consume a large current through the filament circuit, so it turns out that even with an output power of 10...15 W, the amplifier consumes over 100 W from the network.

It is clear that creating a tube amplifier with an output power of 100 W or more to normally drive a fairly powerful compression system is simply pointless: it will consume at least 1 kW from the network and, accordingly, generate heat on a par with an iron or electric stove.

It follows that an open-type speaker system is preferable for a tube amplifier. But it is precisely these systems that virtually no company produces today, either in Russia or abroad. What can the reader do? All he has to do is build such a system himself.

For those who have never done this, it is not as easy as it may seem at first, and that building a high-quality speaker system is no easier than building a high-quality amplifier. Therefore, we will provide not only a detailed description of one of the systems (by no means the most complex), but also accompany it with explanations and comments that will help you competently approach the choice of types of loudspeakers, determine the shape and dimensions of the case and construction materials for its manufacture.

The design of an acoustic system should begin by setting the basic parameters. The main indicators of any acoustic system are:

1. Really reproducible frequency range in terms of sound pressure.
2. Uneven frequency response in this range.
3. Real sound pressure value.
4. Nonlinear distortion factor.
5. Audio signal power consumption.

These parameters are directly related to the choice of types and number of loudspeakers capable of solving this problem. Here again a slight digression into the realm of theory will be required, without which much of the further discussion may turn out to be incomprehensible. Let's start by looking at how a loudspeaker works. To effectively radiate the lowest frequencies, the speaker cone must have the maximum possible radiating surface (cone area), an extremely soft suspension (elastic corrugation and low elasticity of the suspension), which entails a fairly large inertia of the entire system. However, at the lower frequencies of the range this practically does not negatively affect the sound quality of bass instruments.

To effectively reproduce higher frequencies of the range (starting from 8...10 kHz), the requirements for the loudspeaker are reversed. The diffuser can be small in size, but always rigid: very often, to achieve this goal, the paper diffuser is impregnated with bakelite varnish, and the most expensive models (mainly Western companies) are made of plastic or light duralumin. The coil suspension is made rigid and as inertia-free as possible.

Even what has been said is enough to understand that to effectively radiate a wide range of frequencies, one loudspeaker is not enough. Indeed, the vast majority of wideband speaker systems consist of three or more different drivers.

Why three and not two? Because a good low-frequency loudspeaker with a low frequency of its own mechanical resonance effectively emits only frequencies no higher than 4...6 kHz, and high-frequency heads begin to work from 8...10 kHz, so the middle section of the operating range falls into the “failure zone”.

To fill this area, the system usually includes a third, broadband loudspeaker of medium power (3...5 W), to the relatively large diffuser of which a small rigid cone is glued to improve the emission of high frequencies. In this case, it is possible to achieve a frequency band for such loudspeakers ranging from 60...80 Hz to 10...12 kHz with an acceptable degree of unevenness.

1. 6GD-2 RRZ - as the main low-frequency one (frequency band 40...5000 Hz, self-resonance frequency 25...35 Hz, rated power 6 W, impedance 8 Ohms). Used in the highest class stereo radio "Symphony".
2. 4GD-7 - as a mid-frequency “filler” (frequency band 80...12000 Hz, self-resonance frequency 50...70 Hz, rated power 4 W, impedance 4.5 Ohm).
3. 1GD-3 RRZ - as a high-frequency (frequency band 5000...18000 Hz, self-resonance frequency 4500 Hz, rated power 1 W, impedance (at a frequency of 10 kHz) 12.5 Ohms.

It is likely that these particular loudspeakers cannot be purchased today. There is nothing to worry about, since the commercially available types are not only no worse than those indicated, but often surpass them in basic indicators. It is only important when choosing them to adhere to the given nominal power ratios (6:4:1) and, if possible, impedance ratios. It goes without saying that the power rating of replacement speakers cannot be less than those recommended.

Well, for those who do not intend to engage in independent calculations and design, we will provide a detailed description of the simplest, but nevertheless fully meeting the requirements of a Hi-Fi stereo acoustic system, consisting of two identical 10-watt speakers - providing sound coverage of a room with a large margin of up to 50 m and specially designed for the previously described 2x8(10) W stereo amplifier.

So let's start with the case. To make it you will need good, defect-free (preferably aircraft) plywood 10...12 mm thick, thoroughly dried and not warped spruce (in extreme cases, pine) board 30 mm thick, a sheet of plywood 4 mm thick for the rear walls, thin sheet rubber (you can use old car inner tubes), as well as 20 special shipping pads made of loose cardboard, used for packaging and transporting chicken eggs, and good carpentry or casein glue.

In addition, you will need special joinery and carpentry tools for woodworking (longitudinal sawing of thick boards, sawing plywood, planing, cutting holes for loudspeakers in the front board and perforating on the rear walls), as well as wide clamps or clamps for making a glued front panel.

The pictures show drawings of individual parts of the case and its general appearance, indicating the main dimensions. As for the number, shape and size of the holes in the front shield, they will be determined solely by the overall dimensions of the loudspeakers used by the radio amateur and their number. The dimensions shown in the figure correspond to loudspeakers of the 6GD-2 RRZ (low-frequency), 4GD-7 (mid-frequency) and 1GD-3 RRZ (high-frequency) loudspeakers.

It should be noted that when using any other types of loudspeakers, their relative positions and center coordinates on the front panel must be maintained as indicated on the drawing. If instead of one high-frequency loudspeaker two identical ones are used, they must be placed side by side, horizontally and symmetrically relative to the coordinates indicated in the drawing for 1GD-3. They must be connected to each other sequentially and in phase.

Work should begin with the most complex and labor-intensive part - the manufacture of the front shield. This shield is assembled from individual spruce or pine bars, cut from a solid, well-dried, unwarped board with a thickness of at least 30 mm (planed). The board is sawn lengthwise into separate bars with a cross-section of 30x30 mm and a length of 1.1 m (with a technological reserve). After carefully processing the bars with coarse sandpaper, glue a board of the required width (with a small margin) using wood glue or casein glue and, holding it in clamps or clamps, leave it to dry for at least a week.

At this time, you can start making cases. For them, two side, top and bottom panels are cut out of 10 mm plywood, wooden corners are prepared and the acoustic design is assembled using glue and screws. During the assembly process, it is important to maintain the squareness of the structure. This is necessary so that in the future the front board will fall into place without distortion.

The case can be finished with valuable wood veneer (walnut, Karelian birch) or covered with self-adhesive wood-like film. External finishing must be completely completed before final assembly of the unit.

Now you need to make the back walls. They are cut out of 4mm plywood exactly to the size of the rear “window” of the acoustic design.

Then you need to take three egg transport tablets and place them on the table with the “loose” side of the cardboard down. Using a sharp knife or hacksaw blade, you need to cut off flush all the “smooth” cones protruding from the top, then place all three tablets with the cut side on the back wall and use a pencil to mark future holes in the back wall through the holes formed in the tablet.

After all the marked holes have been cut out in the plywood, the back wall should be painted with stain or other water-soluble paint, gauze should be glued on the inside over the entire area, and after it has completely dried, the prepared tablets should be glued on top of the gauze, making sure that the holes in them are exactly located opposite the holes in the back wall. At this point, the production of the rear walls can be considered complete and we can return to the front panel.

If the front panel has dried well and the glue has “tightly” bound the individual bars into a whole board, you need to carefully and with a high degree of accuracy cut it to the desired size. The necessary size is such that after sticking sealing rubber strips-belts on all four end sides of the board, the board fits tightly and without gaps inside the case from the front side. Attaching the board to the case can be done in different ways. The author's designs used mounting angle brackets with washers and wings for attaching the kinescope to the TV case.

When the front board is accurately adjusted to the design opening and covered with rubber strips at the ends, you can begin cutting out holes for the speakers. It should be taken into account that the diameter of the hole in the board must correspond, to the nearest millimeter, to the distance between the inner edges of the cardboard sticker on the speaker on the diffuser side.

After cutting out all the holes, the inner end sides of the holes must be thoroughly sanded with sandpaper, wiped off any resulting dust and coated with any varnish or nitro paint. Now on the outside of the board you need to glue or stretch radio fabric or any other, but always rare (transparent) material using small nails. Only after this can speakers be installed on the front panel, ensuring their absolutely precise alignment relative to the holes in the board.

The remaining six “egg” tablets (for each of the cases) need to be nailed or glued to the inner sides of the side walls of the case (three for each wall) with a “loose” layer of cardboard inside the case. This makes it possible to almost completely eliminate reflections from the side and rear walls of the case and significantly reduce peaks and dips in the frequency response of the unit in terms of sound pressure.

The loudspeakers are connected to each other according to the diagram shown in Fig.

The parameters of the parts indicated in this diagram correspond to the types of loudspeakers used.

Let's consider the phasing of loudspeakers inside speakers and speakers among themselves. This matter is extremely important, because if the phasing is incorrect, even a perfectly assembled system will work very poorly. Unfortunately, many radio amateurs do not know this or do not pay attention to it, paying for the poor performance of good speakers.

The physical meaning of phasing is that in a group of parallel, series or mixed-connected loudspeakers operating from a common two-wire line, when a constant voltage line of positive or negative polarity is applied to the input of the line, the diffusers of all loudspeakers react the same way: either they are pulled into the magnetic gap or pushed out of him. It is unacceptable for the cones of different loudspeakers to move in opposite directions.

In practice, things are a little more complicated. The fact is that the high-frequency loudspeaker is connected to the line through a separating capacitor, and the mid-frequency loudspeaker is shunted by a choke, so when connecting a battery (1.5 V) to the line, you may simply not notice the deflection of the diffuser. So while checking the common mode, the separating capacitor must be short-circuited with a jumper, and the inductor must be unsoldered on one side (either side). To change the phasing of any loudspeaker, you need to swap the wires suitable for it, and after finishing the work, do not forget to restore the temporarily damaged circuit.

After all the speakers inside each speaker are in phase, the speakers should be phased together. To do this, both speakers need to be placed close next to each other at a distance of 2...3 m from the operator “facing” him, turned on in parallel and a signal with a frequency of 200 Hz of a very low level supplied from the sound generator, so that the sound is barely audible . One wire from one of the speakers (any) needs to be broken and a long piece of connecting wire must be inserted into the resulting gap in such a way that the operator, being at a distance of 3 m from the speakers, can alternately close and open the broken circuit.

If, when closing the broken circuit, the volume remains almost unchanged or increases very slightly, then the speakers are phased correctly. If, when connecting a second, open-circuit speaker, the sound volume sharply decreases or the sound ceases to be heard completely, it means that the speakers are turned on in antiphase. In this case, the wires from one of them (no matter which one) must be swapped and once again make sure that the speakers are operating in phase.

After this, the same ends of the wires of both speakers need to be marked (painted over, wrapped with electrical tape, put on a vinyl chloride “stocking”), so that later they can be properly soldered to connectors or other connectors that prevent out-of-phase connection of the two speakers to the outputs of the stereo channels of the amplifier. It is useful to check for common mode again with the amplifier running, since it may turn out that the secondary windings of the output transformers in the two channels of the amplifier have different phases at the output. During such a test, a signal with a frequency of 200 Hz from the generator must be simultaneously applied to both inputs of the amplifier.

Finally, one last note about speakers. Since the current at peak power (10...12 W) exceeds 3 A, the connecting wires must have a sufficient cross-section so that over a length of 3...5 m there is no noticeable drop in signal voltage. It is best to use a standard lighting cord from household electrical appliances as connecting wires for speakers. The wires must be solid; connections in them are not allowed.

Before using the speaker system, you need to check each of them for rattling. To do this, connect a sound generator to the input of the amplifier, set the signal level corresponding to the rated power of the speaker system (in our case, 10 W) and very slowly change the frequency within the entire band, from 40 Hz to 18 kHz, maintaining the output power unchanged and carefully listening to the appearance of extraneous sounds and rattling sounds.

Most often, they are caused by loose washers under screws and screws, a loose back wall, loosely glued sound-absorbing tablets, loosely stretched radio fabric on the front panel, or shavings, sawdust and small foreign objects caught between the diffuser and the radio fabric. All identified causes must be eliminated before using the speaker system.

And if you are not lazy and do everything that was recommended, the author guarantees you excellent sound that will be the envy of the owners of 50 and 100-watt compression speakers.

Greetings to Datagor readers! I want to tell you about creating an acoustic system using 3D printing technology. Using a 3D printer, I was able to build an unusual acoustic system in the shape of a ball, as well as solve a number of additional problems that arise when making acoustics.
I would like to note that I am not at all advocating the use of plastic as the main material for building speakers.

Ever since my student days I had a dream - to make speakers in the shape of balls. But the methods available to me at that time for creating a custom-shaped case did not inspire me in any way. And now, many years later, I got a 3D printer.

Now here is my translation of Troels Gravesen’s article about “the world’s worst dome tweeter Philips AD 0160.” I think he didn’t come across Soviet, or even many modern tweeters.
Most likely, few people have this particular tweeter (tweeter, not to be confused with Twitter), but Troels’ research will be useful for home-made people to evaluate the quality and proper use of tweeters.

Best regards, Sergei

I'll show you with a real example what you can do with old speakers, namely their drivers, to get improved sound.

I would like to tell you about the Sony neodymium dynamic drivers I purchased, manufactured in Vietnam. The Vietnamese are generally great - they make very high-quality things, I always give them preference when shopping. Who doesn’t know, neodymium is a magnet that is lightweight and high in power, which is especially important for manufacturers of home acoustics. In voice coils, neodymium is responsible for transmitting the frequency range, and therefore for the purity of sound and its richness. All these qualities are present in my speakers, which cost me only 750 rubles. - though on sale, as the last product. The declared peak power of these 3.5 inch speakers is up to 200 Watts :-) In Russia, as far as I know, the power differs from both China and Western manufacturers. However, with a 2 x 50 watt amplifier they work perfectly.

Speaker design

So, the goal was to make a homemade enclosure for them that would provide maximum bass transmission and have minimal dimensions, so all these abstruse Internet programs for calculating the speaker enclosure would not work for me.

I designed the speaker cabinet so that the sound would reflect off the cabinet wall, then off the magnet, and out through a fairly large bass reflex port.

Believe it or not, the bass turned out to be quite impressive for such dimensions (h, w, d - 115 x 115 x 130 mm.). To avoid the unnecessary “knocking on wood” effect, I covered the inner walls of the case with mineral wool.

After everything was done, all that remained was to attach the legs to the new speakers, and since they were homemade, I decided to make the legs myself, rather than buy them.

I made oval-shaped indentations in plasticine, filled them with epoxy glue and, after hardening, leveled them in height with a file. I thought about putting an LED in each leg - it would be very unusual, but this is an extra pair of wires, so in general I didn’t.

These acoustic speakers serve as computer speakers for me, but they can be used as rear speakers in a movie theater, or if placed together (they are perfectly sized) they will become a front speaker. That's all, look what happened in the photo. Especially for - Valery K.

Discuss the article SIMPLE HOMEMADE SPEAKERS

1. Column or speaker?
2. Acoustics and electronics
3. What is hi-fi
4. Speakers
5. Acoustics

Making sound speakers with your own hands - this is where many people begin their passion for a complex, but very interesting matter - sound reproduction technology. The initial motivation is often economic considerations: prices for branded electroacoustics are not excessively inflated, but outrageously brazen. If sworn audiophiles, who do not skimp on rare radio tubes for amplifiers and flat silver wire for winding sound transformers, complain on forums that the prices for acoustics and speakers are systematically inflated, then the problem is really serious. Would you like speakers for your home for 1 million rubles? pair? If you please, there are more expensive ones. That's why The materials in this article are designed primarily for very beginners: they need to quickly, simply and inexpensively make sure that the creation of their own hands, all of which cost tens of times less money than a “cool” brand, can “sing” no worse or at least comparable. But probably, some of the above will be a revelation for the masters of amateur electroacoustics- if it is honored with reading by them.

Column or speaker?

A sound column (KZ, sound column) is one of the types of acoustic design of electrodynamic loudspeaker heads (SG, speakers), intended for technical and informational sounding of large public spaces. In general, an acoustic system (AS) consists of a primary sound emitter (S) and its acoustic design, which provides the required sound quality. Home speakers for the most part look like speakers, which is why they are called that. Electroacoustic systems (EAS) also include an electrical part: wires, terminals, isolation filters, built-in audio frequency power amplifiers (UMPA, in active speakers), computing devices (in speakers with digital channel filtering), etc. Acoustic design of household speakers They are usually placed in the body, which is why they look like columns more or less elongated upward.

Acoustics and electronics

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

The rest of the article focuses primarily on how to make speakers that provide good acoustics. The electronic part of electroacoustics is the subject of a special serious discussion, and more than one. Here you only need to note that, firstly, at first you do not need to take on close to ideal, but complex and expensive digital filtering, but use passive filtering using inductive-capacitive filters. For a 2-way speaker, you only need one plug of low- and high-pass filters (LPF/HPF).

There are special programs for calculating AC staircase separating filters, for example. JBL Speaker Shop. However, at home, individual tuning of each plug for a specific instance of speakers, firstly, does not affect production costs in mass production. Secondly, replacing the GG in the AC is required only in exceptional cases. This means that you can approach filtering the frequency channels of speakers in an unconventional way:

1. The frequency of the LF-MF and HF section is taken to be no lower than 6 kHz, otherwise you will not get a sufficiently uniform amplitude-frequency response (AFC) of the entire speaker in the midrange region, which is very bad, see below. In addition, with a high crossover frequency, the filter is inexpensive and compact;
2. The prototypes for calculating the filter are links and half-links of type K filters, because their phase-frequency characteristics (PFC) are absolutely linear. Without this condition, the frequency response in the crossover frequency region will be significantly uneven and overtones will appear in the sound;
3. To obtain the initial data for the calculation, you need to measure the impedance (total electrical resistance) of the LF-MF and HF GG at the crossover frequency. The 4 or 8 ohms indicated in the GG 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 (AFG), tuned to the crossover frequency, with an output of no weaker than 10 V into a load of 600 Ohms through a resistor of obviously high resistance, for example. 1 kOhm. You can use low-power GZCH and high-fidelity UMZCH. Impedance is determined by the ratio of audio frequency (AF) voltages across the resistor and GG;
4. The impedance of the low-frequency-mid-frequency link (GG, head) is taken as the characteristic impedance of the low-pass filter (LPF), and the impedance of the HF head is taken as the head of the high-pass filter (HPF). The fact that they are different is a joke; the output impedance of the UMZCH, which “swings” the speaker, is negligible compared to both;
5. On the UMZCH side, low-pass filter and reflective-type high-pass filter units are installed so as not to overload the amplifier and not take power away from the associated speaker channel. On the contrary, the absorbing links are turned to the GG so that the return from the filter does not produce overtones. Thus, the low-pass filter and high-pass filter of the speaker will have at least a link with a half-link;

When getting into electroacoustics, you need to know the following about how speakers are structured and work in acoustic systems. The speaker exciter is a thin coil of wire that vibrates in the annular gap of the magnetic system under the influence of audio frequency current. The coil is rigidly connected to the actual sound emitter into space - a diffuser (at LF, MF, sometimes at HF) or a thin, very light and rigid dome diaphragm (at HF, rarely at MF). The efficiency of sound emission strongly depends on the diameter of the IZ; more precisely, from its ratio to the wavelength of the emitted frequency, but at the same time, with an increase in the diameter of the IZ, the probability of the occurrence of nonlinear distortions (ND) of sound due to the elasticity of the IZ material also increases; more precisely, not its infinite rigidity. They combat NI in IR by making radiating surfaces from sound-absorbing (anti-acoustic) materials.

The diameter of the diffuser is larger than the diameter of the coil, and in diffuser GGs it and the coil are attached to the speaker body with separate flexible suspensions. The diffuser configuration is a hollow cone with thin walls, with its apex facing the coil. The coil suspension simultaneously holds the top of the diffuser, i.e. its suspension is double. The generatrix of the cone can be rectilinear, parabolic, exponential and hyperbolic. The steeper the diffuser cone converges to the top, the higher the output and the lower the dynamics of the speaker, but at the same time its frequency range narrows and the directivity of the radiation increases (the radiation pattern narrows). Narrowing the pattern also narrows the stereo effect zone 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 sharply reduces the TNI of the GG, because The diffuser suspension is a very noticeable source of sound, and the material for the diaphragm can be very hard. However, the diaphragm is capable of producing sound well only at fairly high frequencies.

The coil and diffuser or diaphragm together with suspensions make up the moving system (MS) of the GG. The PS has a frequency of its own mechanical resonance Fр, at which the mobility of the PS sharply increases, and a quality factor Q. If Q>1, then a speaker without correctly selected and executed acoustic design (see below) at Fр will wheeze at a power less than the rated one, not to mention peak, this is the so-called. locking the GG. Blocking does not apply to distortion, because is a design and manufacturing defect. If 0.7

The efficiency of transferring electrical signal energy to sound waves in the 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), because air is an easily compressible and very fluid medium. The instantaneous acceleration of the coil pushing/pulling the diffuser/diaphragm must be somewhat greater, otherwise it will not “swing” the IZ. A few, but not by 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 more the emitter “slows down”, the more powerfully it emits. In practice, the “braking” of the emitter is done in such a way that its NI in the entire range of frequencies and powers falls within the norm for a given Hi-Fi class.

Note, output: Don't try to "squeeze" out of the speakers what they can't do. For example, a speaker on a 10GDSH-1 can be built with an uneven frequency response in the midrange of 2 dB, but in terms of SOI and dynamics it still reaches Hi-Fi no higher than the initial one.

At frequencies up to Fp, the membrane effect never appears; this is the so-called. piston mode of operation of the GG - the diffuser/diaphragm simply moves back and forth. Higher in frequency, the heavy diffuser can no longer keep up with the coil, membrane radiation begins and intensifies. At a certain frequency, the speaker begins to radiate only like a flexible membrane: at the junction with the suspension, its diffuser is already motionless. At 0.7

The membrane effect dramatically improves the efficiency of the GG, because the instantaneous accelerations of vibrating sections of the IZ surface turn out to be very large. This circumstance is widely used by designers of high-frequency and partly mid-range generators, the distortion spectrum of which immediately goes into ultrasound, as well as when designing generators 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. At zero mode, when the entire surface of the IZ trembles as if to its own rhythm, Hi-Fi up to medium inclusive can be achieved at low frequencies, see below.

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

Woofers

High-quality piston LF GGs (simply “pistons”; in English woofers, barking) are made with a relatively small, thick, heavy and rigid anti-acoustic diffuser on a very soft latex suspension, see position 1 in Fig. Then Fр turns out to be below 40 Hz or even below 30-20 Hz, and Q

The periods of LF waves are long, all this time the diffuser in piston mode must move with acceleration, therefore the diffuser stroke is 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. attached air, the “swing” of which requires significant force (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 recoil of piston engines is small, because It is impossible for a low-frequency diffuser to develop high acceleration at long waves: the elasticity of the air is not enough to absorb the energy given off. It will spread to the sides, and the speaker will go into locking. To increase the efficiency and smoothness of the moving system (to reduce the SOI at high power levels), designers go to great lengths - they use differential magnetic systems, with half-scattering and other exotic ones. SOI is further reduced by filling the magnetic gap with a non-drying rheological fluid. As a result, the best modern “pistons” achieve 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 per pair with differential magnets and rheofill for home acoustics selected for impact, 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 unable to operate in membrane mode.

Piston GGs have one more serious flaw: without strong acoustic damping, they can be mechanically destroyed. Again, simply: behind the piston speaker there must be some kind of air cushion loosely connected to the free space. Otherwise, the diffuser at the peak will be torn off the suspension and it will fly out along with the coil. Therefore, “pistons” cannot be installed in every 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; speaker cones are usually not held by hand and matches are not inserted into the magnetic gap.

Note to craftsmen

There is a well-known “folk” way to increase the efficiency of piston engines: an additional ring magnet is firmly attached with the repelling side to the standard magnetic system from the rear, without changing anything in the dynamics. It is repelling, otherwise, when a signal is given, 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 never before has a single speaker gotten better from rewinding, or at least remained the same.

But that’s not really what we’re talking about. Enthusiasts of this modification claim that the field of the external magnet concentrates the field of the standard one near the coil, which causes the acceleration of the PS and recoil to increase. This is true, but Hi-Fi GG is a very precisely balanced system. The returns actually increase a little. But at its peak, SOI immediately “jumps” so that sound distortions become clearly audible even to inexperienced listeners. At nominal, the sound may become even cleaner, but without Hi-Fi speakers it’s already high-fi.

Presenters

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

The stroke of the MF GG diffuser is made short, because its diameter is comparable to the wavelengths of the midrange and the transfer of energy into the air is not difficult. To increase the attenuation of elastic waves in the diffuser and, accordingly, reduce the NI together with the expansion of the dynamic range, finely chopped silk fibers are added to the mass for casting the Hi-Fi midrange GG diffuser, then the speaker operates in piston mode in almost the entire midrange range. As a result of applying these measures, the dynamics of modern midrange GGs of the average price level turns out to be no worse than 70 dB, and the THD at the nominal value is no higher 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 the SOI.

Tweets

In our opinion - tweeters. As you may have guessed, these are tweeters, HF GG. Spelled with one t, this is not the name of a social network for gossip. Making a good “tweeter” from modern materials would be generally simple (the LR 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 of magnitude or less than the wavelength. Because of this, interference is possible at 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 high-frequency GGs is indicated above: dome ones are universal, and for fans of the classics who definitely require “singing” soft tops, diffuser ones are more suitable. It is better to take these elliptical ones and place them in the speakers, orienting their long axis vertically. Then the speaker pattern in the horizontal plane will be wider, and the stereo area will be larger. There is also an HF GG with a built-in horn on sale. Their power can be taken at 0.15-0.2 of the power of the low-frequency section. As for the technical quality indicators, any HF GG is suitable for Hi-Fi of any level, as long as it is suitable in terms of power.

Shiriki

This is a colloquial nickname for broadband GG (GGSH), which does not require filtering of speaker frequency channels. A simple GGSH emitter with general excitation consists of a LF-MF diffuser and a HF cone rigidly connected to it, pos. 3. This is the so-called. coaxial emitter, which is why GGSH are also called coaxial speakers or simply coaxials.

The idea of ​​the GGSH is to give the membrane mode to the HF cone, where it will not do much harm, and let the diffuser at the LF and at the bottom of the midrange work “on a piston”, for which purpose the LF-MF diffuser is corrugated across. This is how broadband GGs are made for initial, sometimes mid-range Hi-Fi, for example. the mentioned 10GD-36K (10GDSH-1).

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

Coaxial GGSH with separate excitation of LF-MF and HF emitters, pos. 4 do not have this drawback. In them, the HF section is driven by a separate coil from its own magnetic system. The HF coil sleeve passes through the LF-MF coil. The PS and magnetic systems are located coaxially, i.e. along one axis.

GGSH with separate excitation at LF are not inferior to piston GG in all technical parameters and subjective assessments of sound. Modern coaxial speakers can be used to build very compact speakers. The disadvantage is the price. A coaxial for high-end Hi-Fi is usually more expensive than a LF-MF + HF set, although it is cheaper than a LF, MF and HF GG for a 3-way speaker.

Auto

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

Car speakers have a specific task: first of all, to “shout out” the noise in the car’s interior, so their designers don’t particularly struggle with the membrane effect. But for the same reason, car speakers need a wide dynamic range, at least 70 dB, and their diffusers must be made with silk or other measures are used to suppress higher membrane modes - the speaker should not wheeze even in a car while driving.

As a result, car speakers are, in principle, suitable for Hi-Fi up to medium, inclusive, if you choose a suitable acoustic design for them. In all the speakers described below, you can install auto speakers of a suitable size and power, then there will be no need for 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 unsoldering. Modern car speaker speakers allow you to listen to good jazz, rock, even individual works of symphonic music and many chamber music. Of course, they won’t be able to handle Mozart’s violin quartets, but very few people listen to such dynamic and meaningful opuses. A pair of car speakers will cost several times, up to 5 times, less than 2 sets of GG with filter components for a 2-way speaker.

Frisky

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

Manufacturers and sellers do not classify “frisky” people as a special class, because they are not supposed to be hi-fi. The speaker is like a speaker, like any Chinese radio or cheap computer speakers. However, for the “frisky” ones, you can make good speakers for your computer, providing Hi-Fi up to and including average in the vicinity of your desktop.

The fact is that the “fast” ones are capable of reproducing the entire audio range; you just 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 be guided by the manufacturer and its (not trade!) specifications. For example, all GG of the Canadian company Edifier with silk. By the way, Edifier is a French word and is read “ediffier”, and not “idifier” in the English manner.

The frequency response of “fast” ones is equalized in two ways. Small splashes/dips are already removed by silk, and larger bumps and depressions are eliminated by acoustic design with free access to the atmosphere and a damping pre-chamber, see fig; For an example of such an AS, see 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 simply place 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 no bass will be heard at all. This is called an acoustic short circuit. You cannot simply mute the speaker from the rear to the bass: the diffuser will have to strongly compress a small volume of air, which will cause the resonance frequency of the PS to “jump” so high that the speaker simply will not be able to reproduce bass. This implies the main task of any acoustic design: either to extinguish the radiation from the back side of the GG, or to turn it 180 degrees and re-radiate it in phase from the front of the speaker, while at the same time preventing the energy of the diffuser movement from being spent on thermodynamics, i.e. on the compression-expansion of air in the speaker housing. 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 widest and deepest, and the influence of room acoustics on the sound of the speakers is the least.

Note, important consequence: For each speaker enclosure of a specific volume with a specific acoustic design, there is an optimal range of excitation powers. If the power of the IZ is low, it will not pump up the acoustics; the sound will be dull and distorted, especially at low frequencies. An excessively powerful GG will go into thermodynamics, causing blocking to begin.

The purpose of the speaker cabinet with acoustic design is to ensure the best reproduction of low frequencies. Strength, stability, appearance – of course. 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-sized speaker systems, MAS), a bass reflex (FI), passive radiator (PI), direct and reverse horns, quarter-wave (QW) and half-wave (HF) labyrinths.

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

• Unlike others, except FI and PI, the PV labyrinth allows you to improve the bass at frequencies below the natural resonant frequency of the woofer speaker.
• Compared to FI PV, the labyrinth is structurally and simple to set up.
• Compared to PI PV, the labyrinth does not require expensive purchased additional components.
• The elbowed 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 LF GG with both long and short diffuser strokes. Up to replacement in already built speakers. Of course, only a couple. The emitted wave in this case will be practically spherical.
• Unlike everything except a closed box and a HF labyrinth, an acoustic speaker with a MF labyrinth is capable of smoothing out the frequency response of the LF GG.
• Speakers with a PV labyrinth are structurally easily stretched into a tall, thin column, which makes them easier to place in small rooms.

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

PV labyrinth

Acoustic design such as a deep slot (Deep Slot, a type of HF labyrinth), pos. 1 in Fig., and a convolutional inverse horn (item 2). We will touch on the horns later, but as for the deep slot, it is actually a PAS, an acoustic shutter that provides free communication with the atmosphere, but does not release sound: the depth of the slot is a quarter of the wavelength of its tuning frequency. This can be easily verified by using a highly directional microphone to measure the sound levels in front of the speaker and in the opening of the slit. Resonance at multiple frequencies is suppressed by lining the slot with a sound absorber. A speaker with a deep slot also dampens any speaker, but increases its resonant frequency, although less than a closed box.



The initial element of the PV labyrinth is an open half-wave tube, pos. 3. It is unsuitable as an acoustic design: while the wave from the rear reaches the front, its phase will flip another 180 degrees, and the same acoustic short circuit will result. In the frequency response of the PV pipe, it gives a high sharp peak, causing blocking of the GG at the tuning frequency Fn. But what is already important is that Fn and the frequency of the GG’s own resonance f (which is higher – Fр) are theoretically in no way related to each other, i.e. You can count on improved bass below f (Fр).

The simplest way to turn a pipe into a labyrinth 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 wave paths in the pipe will now be of different lengths. In this way, in principle, you can smooth out the frequency response to any predetermined degree of evenness, increasing the number of bends (it should be odd), but in reality it is very rare to use more than 3 bends - wave attenuation in the pipe interferes.

In the chamber PV labyrinth (position 5), the knees are divided into the so-called. Helmholtz resonators - tapering towards the rear end of the cavity. This also improves the damping of the GG, 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 “support” from the side of the last chamber. Having separated the chambers into intermediate resonators, pos. 6, it is possible with a diffuser GG to achieve an frequency response that almost satisfies the requirements of absolute Hi-Fi, but setting up each of a pair of such speakers requires about six months (!) of the work of an experienced specialist. Once upon a time, in a certain narrow circle, a labyrinth-chamber speaker with a separation of chambers was nicknamed Cremona, with a hint of the unique violins of Italian masters.

In fact, to obtain the frequency response for high Hi-Fi, just a couple of cameras per knee is enough. Drawings of speakers of this design are shown in Fig; on the left - Russian design, on the right - Spanish. Both are very good floor-standing acoustics. “For complete happiness,” it would not hurt the Russian woman to borrow the Spanish rigidity connections that support the partition (beech sticks with a diameter of 10 mm), and in return, smooth out the bend of the pipe.



In both of these speakers, another 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 turns out to be 37-45 Hz, depending on the type of low-frequency generator. If the filtered speakers from the S-30B are moved 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 - padding polyester 5-10 mm. Tuning is not always necessary and is not difficult: if the bass is a bit muffled, cover the port symmetrically on both sides with pieces of foam until optimal sound is obtained. This should be done slowly, listening to the same section of the soundtrack each time for 10-15 minutes. It must have strong midranges with a steep attack (control of the midrange!), for example, a violin.

Jet Flow

The chamber labyrinth is successfully combined with the usual convoluted labyrinth. An example is the desktop acoustic system Jet Flow (jet flow) developed by American radio amateurs, which created a real sensation in the 70s, see fig. on right. The inside width of the case is 150-250 mm for speakers 120-220 mm, incl. “fast” and autodynamics. Body material – pine, spruce, MDF. No sound-absorbing lining or adjustment is required. The excitation power range is 5-30 W peak.

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

For the frisky and the computer

It is possible to smooth out the frequency response of car speakers and “fast” ones in an ordinary convoluted labyrinth by installing a compression damping (non-resonating!) pre-chamber in front of the entrance to it, designated K in Fig. below.



This mini-acoustic system is designed for PCs to replace the old cheap ones. The speakers used are the same, but the way they start to sound is simply amazing. If the diffuser is made of silk, otherwise there is no point in fencing the garden. An additional advantage is the cylindrical body, on which the midrange interference is close to minimal; it is less only on the spherical body. Working position – tilted forward and upward (AC – sound spotlight). Excitation power – 0.6-3 W nominal. Assembly is carried out as follows. order (glue - PVA):

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

About horns

Horn speakers have high output (remember why they have a horn in the first place). The old 10GDSH-1 screams through its horn so loudly that your ears wither, and the neighbors “can’t be happier,” which is why many people get carried away with horns. Home speakers use convoluted horns as they are less bulky. The reverse horn is excited by the back radiation of the GG and is similar to the PV labyrinth in that it rotates the phase of the wave by 180 degrees. But otherwise:

1. Structurally and technologically it is much more complicated, see fig. below.
2. It does not improve, but on the contrary, it 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 in principle to correct its frequency response.
3. The radiation from the horn port is significantly directional, and its waveform is more flat than spherical, so one cannot expect a good stereo effect.
4. It does not create a significant acoustic load on the GG and at the same time requires significant power for excitation (let’s also remember whether they whisper into a speaking speaker). The dynamic range of horn speakers can be extended, at best, to basic Hi-Fi, and in piston speakers with a very soft suspension (that is, good and expensive ones), the diffuser breaks out very often when the GG is installed in the horn.
5. Gives more overtones than any other type of acoustic design.



Frame

The housing for the speakers is best assembled using beech dowels and PVA glue; its film retains its damping properties for many years. To assemble, one of the side panels is placed on the floor, the bottom, lid, front and back walls, partitions are placed, see fig. on the right, and cover with the other side. If the external surfaces are subject to final finishing, you can use steel fasteners, but always with gluing and sealing (plasticine, silicone) of non-adhesive seams.



The choice of housing material is much more important for sound quality. The ideal option is a musical spruce without knots (they are a source of overtones), but finding large boards of it for speakers is unrealistic, since spruce trees are very knotty trees. As for the plastic speaker enclosures, they only sound good if they are manufactured in one piece, while amateur home-made ones made from 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, natural wood materials for speakers are difficult: completely straight-grained pine without defects is expensive, and other available building and furniture species produce overtones. It is best to use MDF. The above-mentioned Edifier has long since completely switched to it. The suitability of any other tree for AS can be determined by following. way:

1. The test is carried out in a quiet room, in which you yourself need to first stay in silence for half an hour;
2. A piece of board approx. long. 0.5 m is placed on prisms made from sections of steel angles, laid at a distance of 40-45 cm from each other;
3. The knuckle of a bent finger is used to knock approx. 10 cm from any of the prisms;
4. Repeat tapping exactly in the center of the board.

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

Video: a simple do-it-yourself laminate speaker for your phone

Spikes

Floor-standing and tabletop speakers are installed on special legs - acoustic spikes - which prevent the exchange of vibrations between the speakers and the floor or tabletop. Acoustic spikes are available for sale, but the prices are, you know, a special product. So, weights for construction and carpentry plumb lines have exactly the same configuration (a cylinder turning into a cone with a rounded nose) and material properties. Price - you understand. Feel free to place any speakers on spikes made of plumb weights; they will cope with an unusual task for them perfectly.