The process of creating a do-it-yourself speaker system (hereinafter referred to as the speaker) can be divided into several main stages:

• The choice of the composition of the speakers, based on the requirements for the speaker,
• Payment acoustic design,
• Development of the design and manufacture of the speaker cabinet,
• Calculation and manufacture of a separating filter,
• Debugging.

Starting to design a speaker, it is necessary to formulate the requirements for it:

• Purpose and operating conditions,
• Required sound pressure level,
• Reproducible frequency range,
• Version (with or without built-in amplifier),
• Dimensions and permissible weight.

You also need to decide on the type of construction:

• Acoustic design type,
• Number of stripes,
• Constructive features and design.

Based on this information, you can proceed to the selection of speakers and other system components, to calculate the acoustic design and filters.

Speaker selection criteria have been discussed in detail. A separate one is also devoted to the calculation of filters for speakers on our website. In this article, we will consider the issues of calculating and manufacturing acoustic design for speakers.

So, after choosing the speakers, the acoustic design is calculated, and then they begin to develop the design of the case.

Calculation of acoustic design

Recall that the radiation of the speaker in the low-frequency region is determined by the joint work of the low-frequency speaker and acoustic design. There are several types of acoustic design: open, closed and phase-inverted. The article focuses on phase-inverted systems, since, provided that they are correctly calculated, they have the maximum efficiency of low-frequency radiation, due to which they are widely used among systems intended for professional sound recording.

The calculation of the acoustic design of the phase-inverted type is carried out according to the method proposed by the engineers Thiel and Small. According to this technique, the speaker is a high-pass filter.

The task of calculating AO is reduced to determining the required internal volume and frequency of the phase inverter tuning, which are optimal for a given woofer. The calculation criteria can be different and depend, first of all, on the purpose of the speaker. Systems intended for sounding events, as a rule, should have maximum radiation efficiency in the low frequency range. At the same time, the subjective feeling of "lows" should be preserved as the power is added. The frequency of tuning the bass reflex for such speakers is usually selected on the order of 40-50 Hz. For example, such systems are successfully used for sounding dance floors, where kick is more needed than sub-bass.

Modern methods for calculating the AU imply carrying out computer simulation v special programs... This approach allows you to optimize the speaker not only in terms of the frequency response of sound pressure, but also in terms of a number of other parameters. One of these programs is BassBox 6 Pro. This program allows you to make a comprehensive calculation of the characteristics of the speaker, which is a woofer in acoustic design. The calculation method allows you to find a compromise between the various requirements for the speaker using the method of successive approximations.

Let's consider the basic techniques of working in the BassBox program:

You can enter the program by double clicking on the corresponding shortcut on the desktop.

In the window for selecting a work option (Fig. 1), select OpenDesignWindow(Open project).

Figure 2 shows the main window of the program.

The BassBox program allows you to work with several speakers at once, to compare them with each other by different characteristics... The data for each speaker is stored in a separate tab called Design... Designing a New Speaker begins by creating a new tab by clicking File-> NewDesign.

Button press Driver in the tab Design leads to the opening of the speaker parameters window (Fig. 3). It contains all information related to specific model dynamics.

The data can be entered manually, but it is better to load the required speaker model from the database.

BassBox 6 Pro software contains an extensive database of speakers from well-known world manufacturers. It is possible to add other speakers to this base. To do this, you first need to enter the name of the new manufacturer into the database. To do this, open the menu Edit-> Database-> EditCompanyData(fig. 4). In field Name you should indicate the name of the company and put a tick in front of the item Manufacturer, optionally fill in other fields containing information about the manufacturer, and then click Save.

In the tab Description indicated general information about the dynamics.

In the tab Paramerters the til-small parameters of the speaker are indicated (Fig. 6). In this case, it is not necessary to fill in all the parameter fields, but it is enough to indicate only a few of them. In this case, the rest of the parameters can be calculated using the built-in calculator ( Calc and CalculateAll).

All til-small parameters in dynamics are interconnected with each other. The presence or absence of contradictions between the parameter values ​​is indicated by the color of the signal LED located to the left of the parameter field. The red color of the LED indicates a strong mutual mismatch of parameters, yellow - insignificant, green - no mismatch.

You can also fill in the tab Dimension, which contains information about the geometric dimensions of the speaker (Fig. 7). This information will be automatically used by the program when it becomes necessary to calculate the free internal volume of the case.

After filling in the indicated tabs, click AddthisDrivertoDatabase(Add this speaker to the database).

To retrieve the desired speaker from the database, you need to click LoadfromDatabase(Load from database) in the window DriverProperties(fig. 3). The window shown in Fig. 8 will open. In the drop-down lists, select CompanyName and DriverFound and then press Load.

After loading the basic parameters of the woofer, you need to specify the number of speakers to be installed, the installation method, as well as the interconnection scheme if the number of speakers is more than one. The tab is intended for this. Configuration(fig. 9).

To set the initial parameters of the acoustic design in the project tab Design1 should press Box... This will open a window BoxProperties.

Tab Description is designed to save basic information about the speaker.

Speaker cabinet parameters are set in the tabs BoxDesign(see fig. 10) and Vents(see fig. 11). The first specifies the type of acoustic design (Type = Vented Box - bass reflex), volume (Vb) or dimensions of the body (Dimensions) and the frequency fb of the bass reflex.

In the Vents tab, the design parameters of the FI ports are indicated.

Having set the required parameters of the speaker and body, you can make a trial construction graphic characteristics... To do this, click Plot on the project tab Design... The window shown in Fig. 12 will open. Further, these characteristics can be optimized by changing the parameters of the acoustic design (dimensions of the body and bass reflex).

Let's briefly consider the most important characteristics and the criteria for their assessment:

• NA- AFC of the sound pressure level at a distance of 1m, with a power supply of 1W.

  One must strive to achieve the greatest uniformity;

• CA - Frequency response of the sound pressure level at a distance of 1m, when the rated power is applied.

  Shows the sound pressure that the speaker is capable of providing.

• AP- Acoustic power.

  It is necessary to strive to reduce the depth of the dip in the low frequency region and not to allow a dip of more than 3-4 dB;

• CD- Amplitude of displacement of the cone (voice coil).

  It is necessary to strive not to allow exceeding the maximum amplitude of the voice coil displacement greater than Xmax within the frequency range reproduced by the speaker system;

• VV- The speed of air flow in the pipes of the bass reflex.

  It is necessary to strive to reduce the speed of the air flow in the FI pipe, no more than 15 m / s.

Speaker making

Consider some of the features of the speaker cabinet manufacturing:

In most cases, speaker enclosures are made of plywood with a thickness of 15 and 18 mm.

The structure of the enclosure must be robust and sealed. It should be borne in mind that during the operation of the speaker, an increased pressure is created inside the housing. This circumstance leads to the fact that losses occur in the leaky housing, which are manifested in the fact that air begins to leak out of the slots. This can manifest itself in the appearance of additional overtones during the operation of the speaker. In order to avoid this, all joints must be carefully glued with wood glue. The panels are twisted with self-tapping screws every 7-10cm. The heads of the self-tapping screws are buried and, subsequently, putty.

It is advisable to equip panels of considerable size with stiffening ribs, because in insufficiently reinforced panels, an oscillatory process may occur, leading to a loss of clarity of reproduction of low frequencies. It is undesirable to use a removable cover in the design, because this constructive solution, as a rule, also leads to a decrease in the tightness and rigidity of the case.

All speakers with an open rear side that are part of the speaker, except for the woofers, must be isolated from the internal volume of the case to exclude the influence of low-frequency radiation on them. If you plan to equip the speaker with a built-in amplifier, then it is advisable to allocate a separate camera for it in the speaker case. This is especially true for amplifiers with open printed wiring. When designing a speaker system, it is necessary to ensure the possibility of ventilation of the system components, and take measures to create more favorable conditions for their operation. Let us remind you that during prolonged work on high power the heating of the magnetic circuit of the speaker can reach 70 degrees.

To summarize all of the above, let us remind you once again that making a high-quality speaker requires more than just high-quality speakers. It is important to correctly design and manufacture the speaker case, make a rational choice of drivers (high-frequency heads) and calculate the crossover filter. It should be remembered that the parameters of the loudspeaker housing of the phase-inverted type are calculated in relation to a specific woofer model. You can independently calculate the phase inverter based on Till-small speaker parameters using specialized programs and techniques. Based on the calculated data on the volume of the case and the parameters of the phase inverter, design the speaker case. For the produced loudspeakers, the engineers of the AKTON company have designed loudspeakers that are suitable for most of the sounding tasks. The cabinets of these speakers are optimized for a number of parameters, such as maximum output for low frequencies, the best conditions for thermal convection of the speakers inside the case, shape and dimensions, ease of transportation, etc. A documentation has been developed containing a set of drawings for the manufacture of speaker cases. All speakers have been tested under conditions real work... According to the documentation, the speaker enclosures are made of standard plywood. The outer surface of the body can be painted with paint or covered with a carpet. Technical documentation for speaker enclosures in PDF format posted on our website in the public domain and using it you can make speaker system do it yourself.

Dedicated to those who have free time

We open a popular magazine about good sound and we are happy to look at the graceful images (if not to say the image) of the speaker systems, and there is something to see. Powerful towers bristle in all directions with speakers, shine with their lacquered sides, crush the parquet with sharp spikes and generally evoke a feeling of deep respect. They seem to have only one drawback - of course, the price. A completely logical question arises, but what if you make a copy of a monster yourself? It is not difficult to buy a speaker, to assemble the case, albeit not so beautiful - too, the coils and capacitors can be domestic, carefully soldering 3 parts - this is a task for a student of the 10th grade of the school.

Given the number of ready-made modules that Ebay offers, make good amplifier not much harder. What is not there: switching, speaker protection, class A-AB-D boards, volume controls for every taste, beautiful cases made specifically for audio, handles, legs and transformers - just know connect. In the next article, we will definitely tell you how to assemble your own amplifier, which will not yield to the majority of "branded" samples costing up to 60-70 thousand rubles.

Perhaps later in the text you will come across unfamiliar words. Fortunately, an unknown audiophile came to our aid and left link to your personal archive of information on acoustics and amplifiers, there is really ALL and even more, we strongly recommend that you familiarize yourself.

What to make of? Plywood, MDF, chipboard, plastic, solid wood.

The world has seen many strange acoustic structures, such as concrete or cinder block. All the same, the most "in demand" are the above-mentioned timber-based timber. Let's try to understand which one is "more correct". The basic rule is that regardless of the material chosen, do not skimp on its quality, that is, the price.

The first is the king of the modern Hi-Fi and Hi-End industry - MDF, the vast majority of speakers, both expensive and cheap, are made from it. The reason is simple - low cost, ease of processing and finishing, including options with finished veneer, lack of bright resonances. With proper design, an optimal result is guaranteed. Recommended for use, there is nothing more to say.

Plastic- the concept is very flexible, its "authority" is significantly undermined by cheap Chinese counterfeits, although it has no less advantages than any other material. The problem of the possibility, inaccessible to the amateur, of casting their blanks from the desired material - we pass by.

A good material for making a speaker cabinet can be Chipboard... Perhaps its main drawback is a lot of problems with finishing, no matter what you decide: paint, veneer or fit. Chipboard has a huge plus: if you need to do it quickly and very cheaply, then you can use the factory laminated board (chipboard). In this case, it is unlikely that it will be possible to achieve high aesthetics, but the price and speed will leave far behind all other contenders. If we compare the resonance properties of materials in terms of suitability for columns, chipboard takes the first place, although the difference compared to MDF is small.

Capricious, but invariably desired by "seasoned audiophiles" Mrs. plywood... There are several types of plywood - birch, coniferous, alder, laminated. Why capricious? Any plywood "leads", that is, when it dries, the sheet changes its geometry, and when sawing, chips often appear. It is also not the easiest material to finish if you want to get a "dull" matte color without emerging edges, texture, edges. The reason for enduring these torments is rather controversial: according to the "experienced" only plywood gives the very lively breath that chipboard and MDF "kill". The most incomprehensible to me is the desire to make a body of "living" plywood and "kill" it with layers of putty, primer, paint, varnish in an attempt to hide the "terrible" joints with veins (layers of plywood), which look at their owner day and night with silent reproach ... The options for special impregnation are much more preferable, at least with the same "Danish oil", these dark "stripes" on the edges of the case are not so terrible ...

What kind of beggariness is this chipboard-MDF? Maybe just from solid oak, but thicker !? Do not rush to insert the speaker into the first hole you see. Contrary to expectations array wood of valuable species does not enrich the sound in proportion to the money invested, moreover, it even requires additional damping compared to cheaper materials. Although its undoubted advantages are the convenience of finishing: if the acoustics are assembled carefully, it will not be difficult to bring it to a nice eco-look. Instead of increasing the thickness, it is recommended to add (stick) with back side make another sheet of less resonant material, for example, the same MDF, to make a "sandwich". The most successful option for using an array is a "shield" type acoustics, where a beautiful and heavy front panel is required.

Exotic. Often the choice is due to what is at hand. Just as a bird can masterfully weave any garbage into a nest, so a music lover drags everything that lies badly. You can find on the vastness of the network ideas embodied from plumbing pipes, artificial stone, papier-mâché, cases and cases from musical instruments, primitive building materials, IKEA products, etc., etc.

Where to insert the speaker?

The main task of acoustic design can be formulated as simple language something like this: maximally separate the vibrations emitted by the front side of the speaker cone from the same antiphase vibrations emitted from the back side of the cone. From the point of view of the textbook, the ideal acoustic design is considered to be an endless screen, such an incredibly huge shield in which a speaker is installed. Obviously, the words "incredibly huge" do not fit either our home or our wages, so engineers began to look for a way to "roll up" this screen with minimal negative consequences for the sound. So it turned out all the variety of options, some have won the most extensive fame on the Internet, we will consider them in this article.

Just a speaker or a case without a case

It's hard to imagine that there is such a kind of "acoustics", but flipping through a feed of photos on pinterest on the topic of audio, I more and more often come across bunches of 12-inch speakers, which are assembled together without any design and clearly represent a complete unit. Probably, the author's intention is permeated with the following logic: any case spoils the sound, an acoustic short circuit is better than wooden shackles, but in order to have at least some "bottom", you need to take speakers with the maximum diffuser area, for which there is only enough money. If this is your way - no comment.

Shield and broadband

It is said that those who have tried the lamp, full-range speaker and open design never return to the traditional, transistor-rubber lifestyle. Describing the properties of the shield is not a rewarding occupation, all the necessary information is in the archive, and for the laziest - and on youtube, where they explain in detail what kind of animal it is and what it is eaten with, for example:

The biggest plus of this design is the ease of manufacture. You need a sheet of your favorite material and a jigsaw. The most important criterion that will affect the final sound quality is the cost of the installed dynamic head. The 4a32 speaker has won unabated popular fame for itself, even such giants as fostex, sonido, supravox, sica or the visaton B200 itself are left far behind. The saying "size matters" is the best mathematical formula for a shield (the bigger the better). Next come the variations of the shield, for example, a shield with rolled side walls, a shield in which the low-frequency module is made in the form of a box with a phase inverter, etc. The trademark feature of the sound is "airy" sound with a minimum of resonances, while a relatively high sound pressure.

PAS - acoustic impedance panel

What if you try to cross a shield and a closed box? You will get a box with a back wall, in which many holes are made. The number of holes, their total area in combination with the volume of the box will determine the degree of damping (resistance), the level of low frequencies (the fewer "holes" - the more bass, but also more "booming"). The amount is selected experimentally, to taste.

Linear array of emitters, group emitter (GI)

In fact, this type of acoustics concerns more speakers than the structure of the cabinet itself. I think you have already seen speakers, each of which consists of a large number of identical small, small speakers, well, or not very small, as the budget and living space allows:

By electrical diagram, the heads are connected in series, that is, the "plus" of the previous one is connected to the "minus" of the next one, it is possible to combine a series-parallel connection. The number of speakers, in fact, is also limited only by money, common sense, as a rule, by this time has already disappeared without a trace. Do not think anything bad about me, I tried such a perversion, I even liked it, if possible, I strongly recommend assembling a similar structure for myself, at least for the sake of interest. Again, the budget for this disgrace is not very large, as a rule, domestic speakers in good condition are used, 5gdsh, 8gdsh, 4gd-8e, etc.

Acoustic design - the same shield or a closed box, preferably a cunning shape, for example, a triangular one. One of the problems to be faced is a high total resistance, not every amplifier will reveal the potential of the "array". Serial samples produced at the factory have more complex solutions, speakers are often assembled into cunning modules, filters are added.

Bass reflex,bassreflexport, Helmholtz resonator, aka a box with a "pipe"

Here it is - the most popular acoustic design option. The most profitable in terms of price / result ratio becomes massive, our case is no exception for this rule. For those who have not downloaded the archive of an unknown audiophile, we explain on the fingers. There is a certain volume of air in the phase inverter pipe, which depends on its length, it is also "connected" with the air that is contained inside the column. With a successful tuning of the pipe length (we will not immediately plunge into theory), it is possible to achieve more confident reproduction of low frequencies than just in a closed box. If it's even simpler - with a bass reflex, deep bass is obtained. For a deeper understanding, here is a video from the channel we already love:

Although this type of acoustics is popular, it is far from so easy to manufacture, one pulls after another. Speakers that are suitable for this design are called "compression", most often they have a rubber surround and a frequency band that requires the installation of a high-frequency link, tweeter or tweeter, that is, an electric filter is added. The choice of the optimal volume of the body, its geometry, the precise adjustment of the pipe length are of great importance and do not always correspond to the calculated values. The situation is facilitated by the presence of a mass of projects on the network, where the authors have already passed a thorny path and offer step-by-step instructions with detailed description what, how, from what to do. However, there are always enthusiasts who are not satisfied with the "ready-made" and have enough perseverance to go their own way. The disadvantages of the bass reflex are “bubnezh” and “crushed middle”. The first is solved by careful selection of the shape, diameter, material and length of the pipe; the second is by adding a separate mid-range section. The right path to 3-way acoustics.

Reverse shoutTQWP and other labyrinths of fate

What people have not come up with to complicate the path of vibrations coming from the back of the speaker ... Perhaps the most distinguished company B&W with its Nautilus, even though a monument to this mutant sea shell. But these are giants, and all that we, ordinary audiophiles, can do is recall our nightmares and put planks with nails inside a rectangular box so that this filthy sound does not seem a little. Seriously, there are speakers for which the design of the "bass reflex" type does not fit, and the shield does not give the desired amount of bass, and the appearance of the subwoofer makes something compressed in the stomach. Then the reverse horn comes to the rescue or a more complex version - the labyrinth. For those who are interested in how it works, we wish you a pleasant viewing.

Someone may argue: the reverse horn is not quite a maze, we can partly agree, but what is more reliable - it is closer to the maze than the classic horn:

It reminds of an old gramophone. As you might guess from the name, a reverse horn or labyrinth is far from the easiest type of acoustic design, it requires a good understanding of the theory, accurate calculation, or at least compliance with factory recommendations. For example, large manufacturers of broadband speakers, as a rule, provide a couple of case drawings for their speakers in the documentation.

Onken, closed box (ZY), horn, passive emitter and others

Our story follows in the footsteps of popular popularity, and this is a rather narrow list. A closed box almost always mutters, it is difficult to pick up a speaker for onken, the horn is large in size, difficult to manufacture and calculate, the passive radiator works well, but for some reason it did not take root in the designs of amateurs. Probably, you can find a few more rare species or subspecies of design that did not mention here what to do, you cannot cover everything.

Damping, "packing", "plug"

The enclosures are ready, what to do with them next? That's right, damp. Damping can be divided into two types: vibration absorption and sound absorption. Automotive materials, mastics and special sheets with an adhesive layer, preferably the latter, are well suited for vibration absorption. With sound absorption, confusion and wobbling are observed, someone likes felt, someone likes wool, batting, synthetic winterizer, etc. The answer is quite simple - for a different effect, depending on the type of enclosure and the frequency you want to suppress, the choice of material will depend. Filling the case with sound-absorbing material increases its virtual volume, however, in my opinion, it is impossible to determine a universal standard.

Crossover (Crossover) Setting

You have decided to make multi-band acoustics. Do I need a measurement microphone? If this is a one-time project, then no, it is not necessary, it is enough to have a test set of tracks and some experience to understand which sound can be called more correct. You just have to go through the details of the passive filter longer, listen and compare, but in the end the result will be exactly what your ears and room need. The situation is a little easier with active crossovers. Previously, you had to make them yourself, etch and lay out the boards, solder, a very dreary process, especially if the circuit has a decent cutoff and adjustment steepness, for three-band acoustics it is just a wild thing. Fortunately, today it is enough just to go to ebay and choose an option within your pocket, if you want on opamp, if you want on DSP. You can smoothly adjust the frequency, and sometimes the cutoff slope (in very rare cases, the phase), even every day.

The final

Sometimes it seems to me that the situation in the world of audio resembles the legend of the Tower of Babel. Once upon a time, back when Van Den Hul had never set foot on the ground, people built together one set of home stereo. Big, big speakers, no less big amplifier, and thick, thick cables stretched to them. Someone from above saw this and was horrified - well, game, even if they read some books ... Severe punishment befell the unlucky audiophiles, since then they have been arguing to the point of hoarseness, but they still cannot agree on how to make amplifiers, so everyone makes their own , how can.

At first glance, making speakers based on branded speakers may seem like a fairly simple job. However, in reality, making the speakers yourself is not so easy, it might seem somehow at first glance.

DIY acoustics from scratch

In this article on ours, we will tell you how to properly make acoustics with your own hands based on branded speakers. The crossover is made on metal-film
capacitors and resistors from Jantzen Audio.

Inductors, metal film capacitors and resistors are located on the printed circuit board. For the production of acoustic boxes, we used plywood with a thickness of 18 millimeters. The total volume of the box for acoustics was 13 liters, and the weight of the manufactured speaker was 6 kilograms.

The volume and dimensions of the speakers were calculated using the BassBox 6 Pro program. And the calculation of the crossovers was carried out using the X over 3 Pro plugin. We recommend using Titebond Original Wood Glue. The bass reflex tube was used by Intertechnik BR SL 45. The lining of the acoustics was carried out with a special black Audiomania 101-14 fabric.

Crossover circuit

Acoustic enclosure manufacturing

All required dimensions were obtained using a special utility. It is possible to cut according to the drawing of plywood both independently and entrusted this work experienced professionals. In the latter case, you will receive the highest quality work, which will ensure an effective appearance constructions.

The walls are glued in stages using a special wood glue. To increase the strength of the structure, you can use window glazing beads, which in this case are actually stiffeners. It is necessary to glue the plywood from the inside with batting, which is pre-cut to its original dimensions. This will improve the acoustical performance of the device case.

In the event that you did the cutting yourself, you need to walk along the joints with a milling machine and carefully grind the joints, rounding the edges. After the box is ready, it can be pasted over with a decorative film that imitates the structure of a tree, or you can use a black acoustic fabric. In this case, the choice is solely yours.

We mount the crossover

Typically, crossover testing for acoustics takes on the order of several weeks. During the tests, you need to find the optimal sound, after which you can proceed to the final installation work. The boards for the crossover are glued with silicone sealant or silicone-based glue.

After the sealant has solidified, you can begin to solder the radioelements. When performing this work, you should not spare the solder. The work should be done as well as possible. Having assembled the crossovers, we fix them in the speaker case. You just need to connect the speakers with a crossover with a special speaker cable.

We fix the speakers with self-tapping screws in the case and carefully seal the joint to ensure the maximum possible tightness of the internal capacity of the column. The sound quality of the self-made loudspeakers based on Visaton loudspeakers is at the highest level. In terms of quality, they are not inferior to ready-made branded speakers from well-known brands and, at the same time, the cost of their production is much lower.

Unfortunately, not all of us can afford to have a high-quality speaker system in our home. Now even the cheapest option will cost at least 10 thousand rubles. However, do not buy low-quality speakers that emit a squeaky sound? If you are so eager to have your own in the house, you can do it yourself.

Moreover, all suitable parts and elements can be purchased almost anywhere, and their cost will certainly not be 10 thousand rubles. How to do it yourself? You will learn about this from our today's article.

Instrument preparation

So, in the course of work we need the following materials and tools:

• screwdriver;
• chipboard or MDF sheet (for the manufacture of the speaker cabinet);
• marker;
• jigsaw;
• 400 W PC power supply;
• radio tape recorder;
• Bulgarian;
• a pair of acoustic speakers;
• furniture screws and screws;
• sealant (best used with silicone);
• voltmeter and glue.

Before assembling, first of all, check the operation of the radio and find out whether it can be powered or not. It is also necessary to test the speakers for sound quality. After that, you can safely start making the case and other elements of the speaker system.

Manufacturing of the case

As the walls for the column, you can use a regular MDF or chipboard sheet. At the same time, it is unacceptable to use plywood, since by its characteristics it is very flexible and emits a strong resonance. When making a cabinet for a speaker system, also take into account the fact that the more air remains inside the box, the softer the bass will be. Therefore, leave as much free space as possible, but everything should be in moderation (otherwise, such speakers will simply be impossible to transport).

Place the shelf so that the speakers are exposed to maximum amount air. Next, mark the places for cutting with a marker. Now you can safely cut a chipboard sheet with a jigsaw. Note also that the edges of the trimmed pieces of wood should be carefully leveled. To do this, use a small construction grinder. Please note that it can work with multiple discs - for metal and wood. We need last option, since when processing such materials, the cutting element of the first type is simply erased and even smokes. Experts recommend using a petal circle.

Now the matter remains small. On the case, mark the places for screwing in furniture screws and, using a screwdriver, screw them all the way. In the case of screws, pre-mark for them and drill through holes. Everything, the housing for the speaker system has been successfully manufactured.

Wall fasteners

Emphasis should be placed on the strength of the wall fasteners. Do not skimp on screws and self-tapping screws. The structure of the speaker cabinet should be as strong and sturdy as possible. If the number of screws is not enough, under heavy load, the walls of the system will rattle violently, thereby only degrading the sound quality.

Solid build

How is a three-lane do-it-yourself made next? After you have made the case (the so-called "monoblock"), you can proceed to the fundamental assembly of the structure. The best way to do this is to use a cordless screwdriver with a 4mm Allen key to tighten the screws. Remember that the speaker has its own sound load from minimum to maximum - bottom wall, top, front and side.

How to do it yourself further? In the next step, the joints should be treated with silicone sealant. This is necessary in order to prevent excess from the body from entering out through the slots. Thus, the level of music reproduction will become even better. How to make a do-it-yourself speaker system next? After lubricating all the gaps with sealant, you will need to install the speakers and radio tape recorder. The latter is best purchased assembled. The speakers together with the radio are installed through the holes made into the bottom wall of the monoblock.

When everything is ready, the final view of the structure should have the following appearance: the power supply is located on the back of the monoblock, there are two speakers on the sides (each of them is located in a separate column) and a car radio tape recorder in the middle. Making acoustic systems with your own hands takes place in a certain order of actions - first, the power supply is mounted, and then the radio tape recorder. This will make it much more convenient for you to screw the fasteners. But at this stage, the PC has not yet been finally assembled. Next, you will need to reinforce the hardness of the corners. We will tell you about this in the next section.

How is a do-it-yourself speaker system made? Strengthening the stiffness of the corners

The whole essence of the work consists in pasting certain parts of the monoblock with the subsequent installation of square or triangular glazing beads on them. It is not necessary to use "Moment" as an adhesive. The usual "PVA" will quite cope with this matter. Before applying the adhesive to the surface of the material, make sure it is dry and free from cracks or bends.

What needs to be done in order for the power supply to work?

To do this, you will need to put a jumper on the wide, large connector (in other words, short it). It is enough to use an ordinary paper clip here. You connect two wires (green and black) with it and check the operation of the device with a voltmeter.

In order for these elements to have greater conductivity, after installing the contact, carefully solder their junction points. Now push the block body inside the monoblock and attach it with self-tapping screws. Also seal all formed gaps with sealant.

About sound-permeable material

At the next stage, the speaker system, made by hand, is filled with a special sound-permeable material (here you can use a regular synthetic winterizer). They need to fill the entire volume of the columns.

In this case, you can not apply it to the diaphragm. This sound-permeable material significantly reduces the load on the walls of the system and reduces the speed of sound waves. So, when playing a melody, the speaker structure will practically not vibrate. However, you shouldn't follow the "the more the better" principle. If you overfill the speaker with padding polyester, it can lose bass, and, accordingly, the sound quality will deteriorate significantly.

Fan

If your TV or computer speaker system is designed for high playback power, consider additional cooling elements.

Indeed, under high load, the elements of the speakers become very hot, which can cause their premature failure. And you need to install the fan in such a way that it blows from the inside to the outside, that is, the hot air is brought out into the street (or room). If the heat from the radio is removed, overheating of the system parts will be excluded, and your speakers will last a very long time. At this stage, the question of how to make a three-way speaker system with your own hands can be considered closed.

High-quality sound speakers for home sound amplification equipment reproduce low-frequency signals with a frequency of 30-50 Hz, which corresponds to a sound wavelength of 7-10 m. To efficiently emit such vibrations, dynamic heads with a large cone diameter are needed (there are instances of d 400 mm). However, in practice, the most commonly used "speakers" with a size of 200 to 300 mm. Their own resonant frequency is 15-30 Hz.

When the head is fed sound signal, its mobile system vibrates, emitting in both directions sound vibrations of the same strength, but opposite in phase, which are of an undirected nature. The "speaker" housing is not able to isolate one from another area of ​​compression and depression of air. As a result, the sound pressure level is low at the listening point. This phenomenon is known in the art as acoustic short circuit. Eliminate it by placing the acoustic emitter in a closed box (Fig. 1). (The symbols in the figures denote: a - width, b - depth, c - height of the box, x - thickness of the material, (1 - thickness of the strip). Often one or even several holes are made in it, placing them in certain places of the case (Fig. 2). Such holes are called bass reflexors, or bass reflectors. Their type is a passive radiator (Fig. 3), which is an unconnected dynamic head. sound column are chosen so that the backward radiation coincides with the frontal one, thereby increasing the low-frequency sound pressure.

For loudspeakers, the dimensions, shape and materials from which they are made, the internal "filling" and the design of the front panel are important. Thus, the housing affects the technical parameters of the dynamic head installed in it and, above all, increases its natural resonance frequency. An important role here is played by the diameter of the diffuser and the "displacement" of the body. With an increase in its volume and a decrease in the size of the moving system, the resonant frequency changes insignificantly. If the head with a large diffuser is installed in a relatively small box, the resonant frequency will change noticeably - low frequencies are "cut", and as a result, an effective frequency range the column narrows. In other words, an incorrectly sized body can degrade the reproduction quality of even a very good dynamic head.

For effective return of the head at low frequencies, Bulgarian radio amateurs recommend choosing speaker volumes based on the data given in the table.

When using a bass reflex, certain requirements must also be met. The hole for it should be located at a distance of at least 60-80 mm from the woofer head and 40-50 mm from the rear wall of the case. Sound-absorbing material is placed at the same distance from the hole. It is better if the bass reflex is located under the woofer.

Recommended dimensions for bass reflexes depend on the "displacement" of the column and the diameter of the diffuser head. So, with a head d 125 mm installed in a housing with an internal volume of B dm3, the phase inverter pipe has d 50 (46) mm and b = 60 mm. For a loudspeaker with a volume of 16 dm3, the diameter of the diffuser of which is 160 mm, a pipe of d 50 mm and a length of 100 mm is required. Accordingly, for a head d 200 mm with a volume of Y = 30 dm3, the dimensions of the pipe will be d 75 mm, b = 100 mm. For a loudspeaker d 300 mm, with N4 = 60 dm3, the pipe should have d 75 mm and b = 220 mm.

The shape of the cabinet, both internal and external, also affects the frequency response of a loudspeaker. The most acceptable is a spherical one, and the most inappropriate is a cube, when the dynamic head is located in the geometric center of one of its sides. In a cylindrical body, the most favorable location of the head is transverse (Fig. 4a), and not longitudinal (Fig. 46), although it is much easier to fix it in the latter case.

If the cabinet is the most common parallelepiped shape, the woofer is best positioned asymmetrically with respect to the sides of the reflective board (Fig. 1).

A variation of a parallelepiped-shaped column is shown in Figure 5.

A loudspeaker with a case in the form of a triangular prism (Fig. 6) or a truncated pyramid (Fig. 7, 8) has good acoustic data.

For a volume of 5-10 dm3 and a "speaker" power of 6-10 W, the wall thickness of the box is 8-10 mm, and for V = "40-60 dm3 and a power of 40-100 W, the rest are made of plywood or chipboard. However, with the large dimensions of the case and the significant power of the dynamic head, unwanted vibrations can still occur in it. To avoid them, the walls of the column are pulled together with wooden slats with a section of 40 X40 mm or metal rods d 6-10 mm (Fig. 10).

Bass reflexes are made of plastic or metal (for example, duralumin) pipes with a wall thickness of at least 2 mm.

Minerals are also used as column materials. In the first place is marble. Due to its layered structure, it dampens sound well, and therefore no resonant vibrations occur in it. Marble is easily processed, but as a disadvantage it should be noted that it is heavy and fragile.

The walls of the case are interconnected in one of the ways shown in Figure 11. It is easier to make a drawer with removable front and rear panels.

First, the side walls are cut. Before assembly, it is necessary to glue to them and then nail with small nails the restrictive mounting rails of 15X15 or 20X20 mm and the length shown in Figure 12.

The walls of the case are glued together with Universal or S-200 glue and thin nails are driven in every 15-20 mm for greater reliability of fastening. The box will be even stronger if additional bars are glued in the corners (fig. 13). Free places poured with epoxy. According to the covering assembled in this way, the dimensions of the front and rear panels are determined. They are made from coniferous wood. Based on the available dynamic heads, outline the location of the holes for them (Fig. 14).

The columns are often decorated with decorative frames made of wooden slats with a section of 15 × 15 mm. The radio fabric is pulled onto a reflective board and fixed with buttons or furniture nails.

The internal volume of the column is filled with some kind of sound-absorbing material, such as glass wool. Its amount is determined by measuring the resonant frequency. The body filling is considered normal if it has decreased by 10-12%. It has been experimentally established that this will require 30-40 g of glass wool or 10-15 g of polyester wool (yambolen) per 1 dm3. You can also use rags. Sound absorbing material placed in a cover made of dense fabric.

If the dimensions of the housing are correctly selected and it is carefully sealed, then when you gently press on the diffuser of the low-frequency head, its movable system smoothly returns to its original position. The absence of such a phenomenon indicates the presence of acoustic losses that reduce the sound pressure at low frequencies by 1-2 dB.

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