The subwoofer is an element speaker system, which reproduces the sound of audio tracks at the lowest frequencies. Having a good subwoofer is a music lover's dream, because everyone loves the high-quality sound of music in the car. However, such a device is not cheap. However, most car owners can calculate the box for the subwoofer and make it with their own hands in order to avoid unnecessary spending on the factory model.

How to choose speakers for your subwoofer

Subwoofers are used in cars to improve the sound of music at low frequencies. For normal listening to melodies or radio broadcasts, a standard audio system in a car is quite enough, but connoisseurs of loud and clear sound at low frequencies prefer to place a subwoofer in the cabin.

During the selection of speakers for a future product, the car owner learns that they can be round or oval in shape and size. Usually (based on the dimensions of the car interior), round speakers with a diameter of 10, 13 or 16 cm are selected, as well as oval ones with a length of 15x23 cm. Accordingly, the larger the speaker diameter, the better the sound will be reproduced at low frequencies.

How to know which car speakers are right for you

Before self-manufacturing a subwoofer in a car, you need to clarify a few basic theses:

• the shape of the speakers does not affect the sound quality of music in the car;
• only the size of the speaker affects the depth and richness of the sound;
• it is necessary to think carefully about exactly what shape and size the speakers are needed so that the subwoofer looks appropriate in the cabin.

Design is not paramount, so when choosing a speaker, its priority is specifications

Designing a homemade subwoofer

Car subwoofers are installed in the luggage compartment or on the rear shelf, so this system is called the rear.

The most serious moment in manufacturing is the determination of its size and device. Depending on the tasks set, the design can have a variety of variations.

Types of subwoofers

There are two main types of subwoofers. If we talk about the attitude to the sound power amplifier, then conditionally they are divided into:

• active. They have already built-in amplifier and crossover, which provide high quality sound and remove high frequencies from the sound. The active subwoofer receives signals from any source with which it has a connection;
• passive. The device is not equipped with additional amplifying elements, therefore it is connected to the main audio system of the passenger compartment. The only disadvantage of a passive subwoofer is that it seriously loads all the channels of the system, and therefore the sound quality also decreases.

Active subwoofers do not load the standard interior audio system, so they have better sound quality

Where to install: in the trunk or under the seat

If a active subwoofer can be placed almost anywhere, then the purity and power of its sound at low frequencies will directly depend on the location of the passive device. Depending on the preferences of the car owner and the availability of free spaces in different types of car, several places are offered for installation:

• in the center in front - the optimal position for communication with the front speakers, which will provide almost perfect sounding of tracks in the cabin. However, in most vehicles, there is no room in the front to accommodate any large devices, so the central position in front is more suitable for minibuses;
• in the trunk, with the speaker directed forward - one of the most popular ways for drivers to place a subwoofer. Suitable for all kinds of vehicles;
• in the trunk, with the speaker directed backwards - more suitable for a hatchback car, since the sound wave does not encounter obstacles in its path. The location in the trunk back is unacceptable for sedan or coupe cars, as the sound will be strongly deformed due to the specific design of the luggage compartment;
• on the floor under the seat - another option, which, however, is not very popular with drivers. Due to the fact that the subwoofer is located flush with the floor, in addition, the cabinet is located under the seat, the sound encounters many obstacles in its path;
• on the rear shelf is one of the best subwoofer placement options in all types of vehicles. The main condition is that the shelf must be wide and strong enough to withstand low-frequency bass.

Photo gallery: the main places to place the device in the car

The program algorithm will take into account all the wishes and make the calculation of the volume and other parameters of the case quickly and correctly

What to make a box from

A subwoofer box is not just a box that contains a speaker. The box must comply with many of the dynamic laws of acoustics in order for the sound to be truly rich and clear. For the manufacture of different types boxes will require different materials, and manufacturing methods will in many ways be different from one another.

How to build a bass reflex subwoofer box

The standard version of a homemade subwoofer is a phase inverter. This is the simplest type of subwoofer, besides, its box is good because a special phase inverter tube allows you to reproduce low frequencies that are practically not perceived by the human ear. And the design of the box is quite simple, which makes its manufacture accessible to almost everyone.

Required tools:

• soundproofing;
• wood screws 50 mm long;
• drill;
• screwdriver;
• electric jigsaw;
• liquid Nails;
• sealant;
• PVA glue;
• carpet.

The case for placing a bass-reflex subwoofer must be as durable as possible and not transmit sound waves. For these purposes, multilayer plywood or high quality chipboard is perfect. The best option is to take a plywood sheet 30 mm thick.

For the manufacture of the case, you need to follow this plan:

1. Prepare parts of the body: front, back, two side, bottom and top according to your calculations or the parameters displayed by the programs.
2. Under the size of the speaker (for example, diameter 160 mm), cut a hole in the front of the case blank.
3. Above the hole for the speaker, you will also need to cut a slot for the bass reflex tube and screw the bass reflex compartment to it.
4. After two holes are made on the front panel, it is necessary to glue all the side parts of the box together, and then screw them together with self-tapping screws.
5. In this case, it is especially important to tighten each self-tapping screw all the way, as the empty spaces between the panels will seriously distort the sound of the speaker.
6. Next, on the back of the case, you will need to cut a small hole for the wires.
7. Before connecting all parts of the case, we insert the speaker.
8. Next, it is necessary to carry out the interior decoration of the case: for this, all joints and cracks must be smeared with resin or sealant to increase sealing, after which soundproofing fabric is glued to all side panels.
9. After completing the interior decoration, you need to go to the outside: the body is covered with a Karapet fabric, and the fabric should also cover the slot for the phase inverter. Karapet can be stretched with a regular epoxy or a furniture stapler.

As soon as the speaker is fixed, wires are pulled from it through the hole and connected to the car's speaker system.

Photo gallery: how to assemble a compact box with a phase inverter

The subwoofer can be connected independently, based on the parameters of this circuit

Before starting work, make sure that the vehicle battery is disconnected. This is a safety measure that will not only avoid damage to the speaker system, but can also save the health and performance of parts of the human body.

Video: connecting and setting up a subwoofer

Independent design, manufacture and connection of subwoofers in a car is available to almost every driver. The key to the success of the case will be both a competent calculation of the dimensions and volume of the product, and accurate assembly of the case. At the same time, the motorist can independently choose the desired size of the speakers in order to create the bass sound in the cabin that suits him most.

I decided to write this article specifically for those who want, but for one reason or another cannot afford to purchase a subwoofer. In this article step-by-step instruction about how to assemble a subwoofer with your own hands.

I will try to tell in an accessible language for inexperienced people, and if possible, show that a subwoofer is not at all difficult as it might seem at first glance. If you really want to, but you can’t, then you can!

Many people have this word on their tongue, but not everyone understands what it is.

SUBWOOFER (SUBWOOFER) comes from two words SUB and WOOFER - if literally translated - subwoofer, i.e. speaker system for reproducing sound at lower frequencies (from about 20 to 200 Hz). Many call it - "bass column". Subwoofers can be active or passive. Active - means that an amplifier and a power supply are placed in the speaker case, Passive - accordingly, it needs an external amplifier.

The following abbreviations are also used in the text:

AC - acoustic system, if simply - then "column".

The speaker is also a loudspeaker, but the "dynamic head" would be more correct.

LFO - low frequency signal generator. (under LF we mean frequencies from 20 to 20000 Hz)

ULF - amplifier of low-frequency signals.

Step one.

Tool and material.

To make a subwoofer, we need to find:

1. Self-confidence, the desire to relentlessly go to the end and be prepared for material costs (maybe it will cost good!).

2. A good, proven tool, namely:

Hacksaw for wood;

Chisel;

A set of files of various calibers and types: flat, triangular, round;

Skins (from small to large);

Electric drill;

Screwdriver (you can also use a screwdriver);

Jigsaw (even better - electric jigsaw);

Ruler, pen, pencil, sheet of paper and other stationery;

Compasses (preferably with a wingspan of 20-25 cm.);

PVA glue, auto sealant, wood glue;

Building materials, namely: plywood with a thickness of 10mm to 20mm, chipboard - it is possible but not desirable, wooden bars 20x20, 30x30, 40x40, etc.

A mountain of self-tapping screws from 10mm to 50mm, we will need a lot of them!

3. a computer on which it is highly desirable to install the JBLSpeakerShop program.

Step two.

Loudspeaker (speaker) settings.

Each of us has a first name, last name, patronymic. Each of us has unique facial features, eye color, fingerprint, retinal pattern. There are no identical people in the world. In the same way, there are no identical speakers, each of them has its own unique parameters. Even if you take two identical speakers made at the same factory on the same day, their parameters will differ, of course, a little, but this small difference can be important. Why am I, but to the fact that before we start making a subwoofer, we MUST calculate the main parameters of our speaker. Whether you bought it in a store, unscrewed it from some old speaker, or brought it from a garage, in any case, you need to measure its characteristics. In the future, according to these parameters, we will choose the type of box for the subwoofer.

We will write down the parameters necessary for calculating the subwoofer on a piece of paper and save it until the moment when the sound quality of the manufactured "boom box" is fully satisfactory.

So, let's begin. Since most of the currently existing programs for calculating AC boxes use the Till-Small parameters, we will calculate them.

In order to start calculating the box, we need the following parameters:

Pnom - Rated speaker power, given in the head brand (75GDN-1 75W).
Fs - The natural resonance frequency of the speaker in open space.
Fc - Resonant frequency in a closed box.
Qts - Full quality factor at resonant frequency.
Qes - Electrical quality factor at resonant frequency.
Qms - Mechanical quality factor at resonant frequency.
Vas - Equivalent speaker volume.
D - Effective diffuser diameter.
Xmax - Maximum diffuser displacement. It would be nice to read about all parameters T-S- read.

In principle, other parameters may be needed, but these are already enough to start the calculations.

To measure the parameters, you will need a calculator, a voltmeter (preferably a digital multimeter), a low-frequency generator, a hermetically sealed box of 20 liters, and you will also have to make a simple device.

LF generator - you can take any, for example G3-109 or similar. If there is no generator, then a computer can also be used. We connect an amplifier to the line output of the sound card, and from the output of the amplifier, through a 1 KOM resistor, we connect the speaker under test. The power of the resistor must be 2W or more, otherwise it will get very hot. In principle, everything is ready. If we use a computer instead of a generator, then you need to download the program - LFO, there are a huge number of them on the network.

So, let's begin.

We hang the speaker on a rope in the center of the room to the ceiling, it can be behind a chandelier or in some other way, the main thing is that there are no objects nearby, this can affect the accuracy of the measurement.

All hooked up, run the LFO program, set the frequency to 1000Hz. On the computer, we set the volume to the middle position to eliminate distortion of the waveform. connect a multimeter to the output of the amplifier. By adjusting the volume on the amplifier, we set the voltage to 20V.

We connect the voltmeter directly to the speaker. We set the generator frequency to about 5-10 Hz and gradually increase the frequency and follow the readings of the voltmeter. We need to find the resonant frequency of the speaker, at this frequency the voltmeter will show the maximum voltage, then it will begin to decrease. So the voltmeter showed the maximum value - we write it down in our sheet as Umax. Then we write down the frequency of the generator at which the maximum voltage value is fixed, it will be Fs - the resonant frequency. Now we need to find the minimum value of the amplitude. We begin again to smoothly increase the frequency relative to Fs until the voltmeter readings stop changing, we write this value as Umin, with a further increase in frequency, the amplitude will increase again, but this is no longer important to us.

Now we know a few parameters of our head, but this is just the beginning. With the help of a generator and a voltmeter, we can plot the frequency response shown on the left. It shows Umax - corresponding to the voltage at resonance, as well as Fs - the resonant frequency - the peak on the graph. We also found Umin, but what is Uav, you say, and what are these F1 and F2?

These are the frequencies with which we will determine the quality factor of the speaker. Previously, I calculated these parameters manually, calculated using the formulas Uav, Qts, Qes, Qms. Now there is a useful TSCalc program, you need to download it right now - download. Working with it is elementary simple, we substitute the values ​​- we get the result. First you need to find out Rmax, for this we multiply Umax by 1000 and write the value on a sheet. Still need to measure speaker impedance direct current using an ohmmeter, write it down as Re.

Now let's substitute the values ​​of Rmax and Re into the program and find Rx. Divide Rx by 1000 and get Uav. Now let's find F1 and F2. We begin to reduce the frequency relative to Fs "down" and when the voltmeter shows the voltage Usr we write down F1, now the same thing only "up" from Fs and write down the value of F2. Now we substitute the values ​​Fs, F1, F2 into the program. And we get the values ​​of Qes, Qms, Qts.

It's time for the pre-prepared box. We take our speaker and fasten it to the box with a magnet outside, there is no fundamental difference in this, it's just more convenient. Now we again find the resonant frequency, but we will write it down as Fc. We substitute the value of Fs, Fc and the known volume of the box, we get the value of Vas - the equivalent volume.

Well, that's basically all. The effective diffuser diameter and its maximum displacement are measured using an ordinary ruler. Don't forget to write down the values ​​on the sheet.

Step three.

Types of boxes.

Now we have a speaker, we have its real parameters, we can start choosing a box.

I want to disappoint. It is according to the parameters of the speaker that the type of case is selected. I'm not saying that it will not be possible to assemble the box that you want on it, it just may not sound the same as it would sound in the "native" box.

So, the types of boxes, or subwoofer options.

Option one - Free emitter or Free air.

This option may be suitable for speakers with Fs above 100Hz.

A travel subwoofer will not come out of it anyway, since its parameters are close to midrange speakers. For example, it can be built into the rear shelf of the car.

Of course, you can try to make something else out of it, but it's better to look for another speaker.

Option two - Closed box or Closed Box.

Select this box if Qts<0,8...1, оптимально 0,7

product Fs/Qts=50

It is easy to calculate, all you need to do is calculate the volume of the box.

A lot of power is required from the speaker, the probability of its failure is very high. In most cases, the box turns out to be bulky, which is completely unacceptable for home and car.

The inside of the box is filled with sound-absorbing material, cotton wool, felt, etc.

This embodiment has the lowest efficiency.

Option three - Phase inverter or Vented Box.

Choose if Qts<0,6, оптимально 0,39

The speaker must have a flexible and durable suspension, because. performs gigantic work, at maximum power input, the diffuser oscillates a huge amount of air, most of which "flies into the pipe"

Option four - Passive radiator - Passive Radiator.

A passive radiator is like a phase inverter, but instead of a tube, there is an emitter-membrane.

Although you can use the old speaker, remove the magnet, basket, diffuser. And glue a plate of getinax, plexiglass or other material to the rubber suspension. We screw the load into the center of the plate - a bolt with a nut. Fc can be adjusted with this weight.

Option five - Band Pass or Band Pass

The Band Pass can be transported as a Band Pass.

Band Pass 4th order- Band Pass 4th order.

Worth choosing if Fs/Qts=105

In principle, of all the other case options, it is this one that has the highest efficiency.

But at the same time, the most difficult to manufacture, two cameras and two phase inverters.

Band Pass 6-th order A - Band Pass 6th order class A.

Band Pass 6th order B - Band Pass 6th order class B

Any of these enclosure options can be assembled on one or two speakers.

You know the parameters of your speaker, what will come out of it, you have already determined, it's time to calculate the box.

Step four.

Box calculation.

Unpack the downloaded JBLSpeakerShop program to the root folder of the disk. Then we run the setup.exe file from the DISK1 folder. The installation will begin, enter the path of the second part of the DISK2 archive. Installation completed.

Run the program Start=>Programs=>JBL SpeakerShop=>SpeakerShop Enclosure Module.

I will not talk about the program in detail, it is very simple and in principle everything is clear.

First, go to the Loudspeaker menu - and enter the parameters of our head. Then, having selected the box type, click - Box - Parameters - and there already on the selected type. it remains to enter the volume and frequency of the desired resonance, you need to experiment with these parameters, observing the resulting graphs. After you have chosen the parameters of the box, click Vent, here we enter the parameters of the pipe (phase inverter), if there is one, of course. It remains to calculate the dimensions of the box, the Dimensions submenu, choose the shape and size to your liking. In the Graphs menu - select the types of graphs to be displayed.

To the eyeballs, we print out graphs, parameters, sizes - Ctrl + P.

Step five, final.

Box manufacturing.

Now, after a little rest, let's start making a box. At this stage, in order not to translate precious material, one must strictly observe the rule, "measure seven times, drink once."

We get the prepared tool, material, patience. When choosing plywood or chipboard (who has what), you need to take into account that the higher the power of the speaker, the higher the wall thickness of the box should be and the stronger the mount. The best material, of course, is plywood (you should not use an old, dried one - it will simply crumble with you), much stronger than chipboard, I don’t understand at all how you can make a good subwoofer from sawdust.

We took out a ruler, a pencil, first of all we draw all sides of the box on a sheet of plywood. Try to save, suddenly you make a mistake somewhere, there will be something to correct.

Now let's cut it, a hacksaw with a guide and small teeth will be a good tool. You need to cut slowly and preferably at an angle, you do not want the plywood to exfoliate and crack. You can also use a jigsaw, preferably with a speed controller, for the reasons already stated. Saw smoothly, do not rush, you are tormented by a file to straighten humps and cavities.

After you have cut it, you still have to work with a file, you need to remove all the protruding pieces of wood, otherwise splinters, iodine, bandages.

We got wooden blocks, choose their sizes yourself, but of course not too small or huge. Attach the walls to each other as they should be and measure the required length of the bars.

Another crucial moment in the manufacture of the box is a huge hole for the speaker. First, with a compass, we mark a circle under the speaker, slightly larger than the diameter of the diffuser, along with a rubber suspension. And another smaller circle, equal to the radius of the drill and adding another 2-3mm. Here are a few ways to pierce a piece of plywood. Do not look for a drill, it is unlikely that there are drills with a diameter of 100-300 mm in the world, and a giant drill will be needed. Take a drill with a diameter of 10-15mm, an ordinary electric drill. Drill by laying your piece of plywood on top of some other scrap wood sheet, this will keep the bottom surface from cracking a bit. Now, along the inner circumference, we drill holes at a distance of 1-2 mm from each other. When you're done, take a narrow chisel and a hammer and pierce the bridges between the holes, then knock out the resulting pancake. We take the largest round file, or rather a rasp and slowly, again at a slight angle, align the circle along the drawn line. Sharp corners on the front side can be rounded off. In the same way, we make holes for the phase inverter. Another way: draw a circle with a diffuser radius and a hole inside, and then use a jigsaw to cut along the line. Faster, but more chips! Attach a speaker to the hole, if the "hole" suits you, drill holes for the head fastener, and for fastening you can use double-sided screw-in metal nuts, they are used in the furniture industry.

Don't forget the split! It is better to use from concert acoustics - it is more reliable and more practical.

Well, we made all the walls, holes for the speaker and phase inverter, drank the bars, we will assemble them.

Again, behind the drill, we put a drill twice as small in diameter as the self-tapping screws and drill sheets of plywood in those places where it will be attached with other sheets and bars. Now we take PVA glue or wood glue and smear it thicker at the joints. We connect the walls together and screw the self-tapping screws into the holes made, it’s not scary if they go through, you can’t see inside, and strength is important to us. The adhesive will play two roles, increasing the strength of the fastener and sealing. Make sure that the design does not warp, the corners are even, because there must be beauty and accuracy.

Do not screw the back wall yet, it will still serve us. Fasten the speaker, from the outside or from the inside, as you like and depending on what speaker design. Coat the junction of the plywood with the speaker with auto-sealant, being careful not to get on the cone. Autosealant - will ensure tightness and is easily removed if you suddenly want to change the head to another one or during repairs.

Phase inverter - you can use a piece of a plumbing pipe, an aluminum pipe, and, in principle, any pipe you have (except for metal water and sewer pipes). In the program, enter its dimensions and get the length. The phase inverter can also be square, then you will need to show your imagination in its manufacture. It will also need to be fixed, but not yet tightly.

How to make a damper The damper material can be: felt, hard foam rubber, cotton wool, thick vorsonite, etc. The most accessible material is cotton wool. But you can't just stuff it inside! Here, our beloved women will come to our aid, who, all the time of our efforts, grumble about garbage, noise and a bunch of tools mixed with pieces of wood, etc. How can they help us? Yes, it's very simple, women's tights, you can stuff cotton wool into them and make sound-absorbing "sausages", which we will stick to the walls of the box.

Setting the phase inverter. After damping, put the back cover in place, but so that you can then remove it. Although if your speaker is pulled out, then the back wall can be fixed tightly with glue and a bunch of screws. We connect the unit to the low-frequency generator through an amplifier, and a voltmeter to the contacts of the subwoofer (i.e., the speaker located inside). By changing the frequency of the generator, we find the resonant frequency Fc according to the already known method. If the resonant frequency differs from the calculated one, we will adjust it using a phase inverter and the amount of damper inside the box. The phase inverter pipe will need to either be shortened or lengthened, in some cases the pipe may be longer than the dimensions of the subwoofer, in which case it can be bent in the form of the letter "G". You also need to experiment with the amount of damper, remove or add, decide on a specific situation. When the resonant frequency suits you, you can tightly fix the phase inverter, damper.

Turn on the music, the louder the better, listen if you don't extraneous noise, whistle, rustle. If it whistles, it means that somewhere in the box there is a hole or a gap left open, cover it with putty or sealant, fill it with glue. If it rustles, the damper may be hitting the moving speaker cone.

Now the final external processing of the box, the corners can be rounded, carefully sanded, cover the cracks and pits with mastic or putty.

In the end, you can paste over the subwoofer with vorsonite or some other material, put decorative grilles on the speaker and bass reflex, screw the legs if you are going to use it indoors, fantasy will tell you here.

Well, that's it, that's all! I hope all my writings helped someone! Thank you for reading to the end, all the best to you, success!

Send your comments, corrections, questions to [email protected]

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A subwoofer, also known as a "bass speaker", is a separate acoustic element that reproduces audio frequencies in the ranges of 20…120 Hz. Speaking figuratively, within the framework of the entire acoustic layout, the subwoofer occupies the low frequency range, while the entire speaker system reproduces medium and high frequencies.
Subwoofers are divided into active and passive, the former have a power supply with an amplifier mounted in the case, while the latter have an amplifier connected externally.

We make a subwoofer

This manual is written specifically for those who dream of having a 5 1 with a subwoofer installed in their car, but for one reason or another, they cannot afford to purchase a subwoofer. Making an acoustic subwoofer yourself is not at all difficult, and due to the fact that human hearing does not recognize the direction of low-frequency waves, you can install a subwoofer in a car in any accessible place.

Tools

In order for your thought to materialize into the image of a subwoofer, in addition to wild desire and “stubbornness”, we need a couple more little things:

• Hacksaw for wood;
• Chisel;
• A set of files (triangular, round, flat ... what else is there ...);
• Sandpaper of different caliber (grain);
• Screwdriver or screwdriver set
• Electric drill;
• Jigsaw, preferably with a "non-manual drive";
• A set of stationery, where the compass has a "span" of at least the diameter of the selected speaker (20 ... 25 centimeters);
• Glue for wood;
• Building material for the body (plywood, chipboard, MDF 10 ... 20 mm thick);
• Wooden blocks (for stiffeners) with a section of 20x20 ... 40x40 millimeters;
• A bunch of self-tapping screws (from 10 to 50 millimeters);
• Program for calculating subwoofer parameters (JBLSpeakerShop, WinISD 0.44, etc.).

So, we begin the creation of a low-frequency column with the choice of a speaker (see).

Speaker selection

Since you are not the first music lover on this earth, it must be assumed that some well-established canons in the world of music already exist, the above also applies to the use of speakers:

• Six inch are used as an additional source of mid-bass;
• Eight inch are responsible for the frontal bass;
• High-quality acoustics on a car is obtained with ten inch speakers installed in a 15 ... 20 liter case;
• The best option is a twelve-inch speaker in a 25..35 liter case;
• Well, fifteen inch housed in a 60..90 liter case, as a rule, is in the hands of true "maniacs" and is put on display to the venerable public during the SPL competition.

By the way, both among amateurs and among professionals there is still no agreement on the power of the speaker. But at the moment it can definitely be argued that the speaker should definitely be more powerful than the amplifier, since no system is able to reproduce an audio signal for a long time, at maximum volume, without the appearance of non-linear distortion and a significant decrease in sound quality, everything must be balanced here .
We select the speaker that suits us, of course, the more powerful it is, the louder the sound will be. It doesn’t matter which way you got it, how it got to you, we need to know its technical characteristics, because a very important stage depends on them - the design of the case.

Calculation of parameters

If you do not have the accompanying documentation with the technical data of the speaker, and there is no way to find out these parameters from the manufacturer, then we will have to calculate them ourselves.
We will need to find out information about:

• The rated power of the speaker (usually given in the head marking - 75GDN-1 75 W) - Pnom;
• Natural resonance frequency - Fs;
• Natural resonance frequency in a closed space - Fc;
• Speaker equivalent volume - Vas;
• The largest diffuser displacement - Xmax
• Effective diffuser diameter - D;

Well, about the indications of the quality factor of resonant frequencies:

• Full - Qts
• Electric - Qes;
• Mechanical - Qms.

To get the necessary parameters, we need:

• Digital multimeter (voltmeter);
• Calculator;
• Any low-frequency generator, for example, GZ - 109 (instead, you can use the low-frequency generator program on a computer, since there are a great many of them on the network);
• 20 liter, hermetically sealed box.

So to sound card, through the line output we connect the "amp", and from its outputs, through a resistor with a nominal value of 1 KOM, a speaker is connected (see photo):

• In order to avoid the influence of third-party objects on the quality of measurements, we hang the speaker in the middle of the room on a chandelier. Next, we launch the LFO “program”, set the frequency to 1000 Hz and set the average position of the volume control on the computer;
• To eliminate signal distortion, we connect the multimeter to the “amplifier” output and, by adjusting the volume on it, set the voltage to 20 Volts;

• We connect the multimeter to the speaker;
• We increase the frequency of the generator (starting from a frequency of 5 ... 10 Hz), monitor the voltmeter data until the desired frequency of the speaker at maximum voltage (Umax) reaches its maximum, after which it begins to decrease. The generator readings, at which Umax reached its maximum on the voltmeter, are recorded as Fs data;
• We smoothly increase the frequency relative to Fs until the readings stop changing. We write down the value of Umin (a further increase in frequency, of course, will cause an increase in amplitude, but these data are no longer important to us);

We can already express the obtained data in the form of a graph of the amplitude-frequency characteristic of the speaker:

When viewing the graph, you can observe the new introductory Uav, F1 and F2, these are the frequencies with which we will determine the quality factor of the speaker using the formulas Qes, Qts, Qms and Uav.
Previously, calculations were made manually, but now everything is extremely simple - download the TSCalc program, insert the known values ​​​​and get the result:

• Value Rmax=Umax*1000;
• Re value = DC speaker resistance value;
• Substituting these values ​​into the program, we get Rx;
• Usr = Rx/1000
• F1 is looking for by decreasing the frequency down relative to Fs until the voltmeter shows the value Uav;
• F2 we are looking for similarly, only we raise the frequency already up;
• Substituting the obtained values ​​of F1, F2 and Fs, we obtain the desired data on the quality factor of resonant frequencies.
• Next, we need to find the resonant frequency of the speaker in a closed space - Fc. To do this, we fix the speaker with a magnet outward (it doesn’t matter, it’s just more convenient) in a pre-prepared box, and look for what we are looking for in the same way as the Fs value.
• Substituting the values ​​of the volume of the box already known to us, as well as the found data Fc and Fs, we obtain the values ​​​​of the equivalent volume - Vas;
• The effective diameter and the maximum displacement of the diffuser are found using a ruler.

Drawer selection

Now that we know all the necessary parameters, we can begin to select the type of subwoofer enclosure.

Attention! No matter how much I want to upset you, but only the parameters obtained (and not your desires) are the main factors determining the type of hull. This does not mean that you will not be able to assemble the type of case you have chosen, but whether it will produce the sound we need is a question ...

Free air (free emitter)

This type of speaker is suitable when Fs > 100 Hz. As you might guess, a travel subwoofer will not work out of it, since it almost completely lacks a sub-low frequency range.
The maximum where it can be determined is the rear of the car, but the best option would be to search for another speaker.

Closed Box (closed box)

We choose this type if the value of Qts is less than 0.8-1.0 (optimally 0.7), and Fs / Qts is 50. It is not at all difficult to calculate it.

Vented Box (phase inverter)

Optimal when Qts is less than 0.6 (optimum is 0.39), and Fs / Qts is 85. More difficult to design.

Band Pass (band approach)

It has the highest efficiency, and at the same time is the most difficult to manufacture. Best when Fs/Qts is 105.

PassiveRadiator (passive radiator)

The same phase inverter, only a membrane emitter is installed in place of the pipe. The calculation of its parameters is similar to a phase inverter, but it is a little more difficult to manufacture.
Although if you take an old speaker, dismantle a magnet, a diffuser and a basket from its case, glue a plate of plexiglass (getinax, etc.) to the rubber clip, and screw a weight (bolt with nut) into its center with which you can adjust Fc, then you will get a very good and not expensive PassiveRadiator.
Any of the options presented can be made with one or two speakers. So, we know the parameters, we have decided on the type of hull, it's time to start calculating the hull.

Box calculation

AT this case I decided to use the JBLSpeakerShop program.

Do not expect details from me, this “program” is very simple and understandable (by the way, video instructions on the Internet are always at your service).
But I will still tell you the procedure:

• Download the program and run it through the “setup.exe” file located in the first disk, after which we indicate the path to the second part of the installation file;
• We launch the program and go to the “Loadspeaker” menu where we enter the parameters of the head;

• We select the box type and go to “Box - Parameters”, where on the selected option we enter the frequency and volume of the desired resonance (when entering these parameters, you can improvise and observe the result on the graphs);
• Further, after the parameters are selected, if your subwoofer has a phase inverter, activate the "Vent" key and enter the pipe parameters;
• In the "Dimensions" submenu, select the shape and dimensions of the box;

• In the "Grafs" menu, select the displayed graph;
• Print the result - "Ctrl + P".

Making a subwoofer box

Training

As you know, practice is the criterion of truth, but since the calculation is completed, we proceed to the most interesting part of our instructions, where one rule reigns - measure seven times, cut one.

Advice! When choosing a case material, it is necessary to take into account that the greater the power of the speaker, the thicker its wall should be, and the mounts should be more rigid.

So:

• We take a prepared sheet of high-quality (not dried and not old) plywood, which is an order of magnitude stronger than chipboard, and draw all sides of the box on it.

• Saving at this stage is not worth it - then there will be nothing to correct mistakes.

• If you have a hacksaw with a "manual drive", then it is better to choose with small teeth and with a guide. To avoid delamination and cracking, cut slowly, at an angle, the above is also true when working with an electric jigsaw.
• With a file, we process all the protruding fragments of plywood and compare the humps and depressions resulting from sawing off.
• We measure the bars and saw them to size, for which we “estimate” the body from the sawn parts and take measurements.

One of the crucial moments is the manufacture of a hole for the speaker.
Since it is somehow problematic to find a drill with a diameter of 150 ... 300 millimeters, we will think with our heads:

• We measure the diffuser with a rubber clip and, taking a slightly larger value, measure the circumference on plywood with a compass. Next, we retreat from this line inward by the radius of the selected drill (adding a couple more millimeters), we mark a circle of smaller diameter.

Method one

We drill a line of a small circle with a drill for 10 ... 15 millimeters, insert a jigsaw file into the resulting hole and cut out the hole, drawing the file along a large circle.

Advice! Put the plywood on some hard surface before starting drilling - this way, at the exit, the drill will not “pull” the back wall.

Method two

It is not necessary to draw a second circle - we drill a hole anywhere inside the circle, insert a jigsaw file and smoothly bring it to the line of the drawn circle.

Method three

Along the entire diameter of the small circle, we drill holes near each other, after which we break through the jumpers between them and process the circle with a file.

Estimate the speaker by the hole, and if everything suits you, drill holes for the mounting nuts, which can be purchased at any department of furniture fittings.

Advice! The connectors used in concert acoustics are very practical and reliable, it is best to use them.

Box assembly

So, the holes for the speaker and the phase inverter are made, the bars are sawn, we proceed to the assembly work:

• We take a drill with a diameter two times smaller than the diameter of the self-tapping screw and drill sheets of plywood in those places where they will dock with the bars and with other walls;
• Before joining the parts with a thick layer, we coat the points of contact between the walls and the bars. A thick layer of glue in our case performs two functions at the same time - it increases the strength of the structure and seals the joints;

Advice! Screw the back wall at the last assembly step.

• We install the speaker, while we coat the place where the diffuser and plywood join with an automotive, water-repellent sealant (good sealing of the seam +, if necessary, can be easily removed);
• We make a phase inverter from improvised materials of a round shape (except for metal pipes, pieces of water supply and sewerage), entering the diameter of the pipe into the program and getting the value of its length. It’s not worth fixing tightly yet, we still have to adjust it.

By the way, the phase inverter can also be square, in which case you will have to fantasize a little in the process of its manufacture:

Any sound-absorbing material can be used as a damping material, for example, a thick layer of vorsonite, felt, cotton wool, hard foam rubber, etc.

• At the time of tuning, we put the back cover of the box in place;
• We connect the unit through an amplifier to a low-frequency generator, and a voltmeter to the speaker contacts;
• By changing the frequency of the generator, according to the method described above, we find the value of Fc;
• If the desired value differs from the calculated one, then by changing the parameters of the phase inverter and the amount of damping material inside the subwoofer box, we experimentally find exactly the moment when the resonant frequency will suit us completely.
• In the case when the calculated length of the phase inverter pipe exceeds the length of the subwoofer itself, its diameter should be changed;
• We finish the assembly work, fixing all the remaining parts "tightly".

This concludes the instructions for making a car subwoofer with your own hands. You just have to check your work in action.
We turn on the hardest version of the musical composition at full volume and listen to what is being played for the appearance of extraneous noise, rustling, whistling:

• The whistle indicates the gap remaining inside the open space, the hole which should be covered with sealant, putty or glue;
• Rustle means that the moving damper of the speaker is in contact with its cone.

Finishing external processing subwoofer: we round off sharp corners, sand it, cover the pits and cracks with putty or mastic, after which we glue it with material and install decorative grilles on the speaker cone and phase inverter pipe.
That's all. I hope you will be pleased not only with the price of your "brainchild", but also with the excellent quality of its sound.
After all, if you did everything right, then without your prompting, hardly anyone will guess that the powerful and clear bass coming from the inside of your car is reproduced from a homemade subwoofer. Which, by the way, is not ashamed to boast)))

I spent the next week working on the subwoofer. I downloaded several programs for calculating subwoofer enclosures (DLSBox2000, JBL-Speakershop, WinISD ...) Most of all I liked the DLSBox2000 program. With her help, and calculated the sub. And here's what happened - the efficiency of this design (FI) for my speaker is 76%, the volume is 37 lire (with external dimensions 45x35x35cm.), The phase inverter is 75x100mm. (diameter/length).

Then he drew a sketch on paper, and began to manufacture it.

I screwed all the walls with 50mm long screws. All connections are planted on PVA glue (advice - no need to feel sorry for the glue, the excess will squeeze out). Inside, for greater reliability, the seams were smeared with silicone sealant. In principle, this is not necessary, but it is better to miss and forget than to disassemble again later.

Then proceeded to puttying. Putty used automotive, two-component (You can make putty yourself by mixing small sawdust of wood and PVA glue, as an option). When the putty was dry, I sanded the body almost to the ideal plane.

Then I cut out holes for a phase inverter, a socket, for handle-pockets.

We collect a subwoofer in order to see how it sounds.

All my doubts about the correctness of calculating the volume of the box were dispelled in an instant - a home-made subwoofer played a soft, even bass. After making sure that nothing whistles anywhere, I took off the “fittings” and proceeded to pasting the case with self-adhesive paper with a leather texture. Collected.

Subwoofer Manufacturing Costs:
Woofer Semtoni 10 "(25 cm) 350w (rms, max) - 1100 rubles.
Chipboard 20mm. – free, found in the attic
PVA glue - free, was already in stock
Self-tapping screws 50mm. 100 pieces. - 26 rubles
Silicone sealant, transparent - 59 rubles
Sealant gun - 40 rubles
Socket with terminals - 65 rubles
Acoustic wire 1m. - 60 rubles
Phase inverter 75x100mm. - 40 rubles
Handles "Pockets" 2 pcs. - 100 rubles

Total about 1800 rubles.

Modern sound technologies are developing at an active pace, and your own cool subwoofer for the home no longer surprises anyone. The main purpose of this component of the audio system is to reproduce a low frequency range (not higher than 100 Hz), which are not reproduced by ordinary speakers. Which model to give preference? What parameters to consider when choosing? Let's try to figure it out.

Main purpose

A subwoofer is equipment that provides quality, for example, when listening to music or watching a movie at home. Such devices quickly gained popularity and became an important component of a powerful speaker system. When choosing a subwoofer for your home, you need to proceed from indicators such as power and purpose. Note that there are two main types of these systems:

• Active. They are ideal for home theater use due to their flexibility and ease of installation. Such devices are cheaper.
• Passive. Subwoofers of this type are originally designed in such a way that they can only be used in combination with an amplifier. In this case, the amplifier must be of sufficient power.

An active subwoofer for the home is a more convenient and correct solution due to the built-in filter and low-frequency amplifier. Thanks to this, the sound acquires a higher quality at any frequency. At the same time, using an active subwoofer, you can improve the distorted sound throughout the entire range.

Rating of the best

Modern manufacturers offer various models of subwoofers that are suitable for home use. They differ not only in cost, but also in a number of options and functions. If you want to choose the best subwoofer for your home, we suggest that you familiarize yourself with several of the most popular models.

YAMAHA

YAMAHA YST-FSW100

This subwoofer has a power of up to 80 watts and is inexpensive, so it quickly gained popularity among buyers. High quality, minimum sound leakage, correct sound direction - all this distinguishes this model. The design solution of the device is such that there is no blockage at low frequencies. As a bonus, the manufacturer offers magnetic protection that will prevent sound distortion if monitors or TVs are located nearby.

YAMAHA YST-SW012

Another Japanese subwoofer for the home is a floorstanding accessory that already comes with a built-in amplifier. The phase inverter filling makes the device sensitive to any frequencies of the operating range, creating high-quality sound in the room. Among the advantages of this model, one can note the minimum number of settings and adjustments, small dimensions and an affordable price.

ONKYO SKW-770

This model, with its small size, has a power of up to 150 W, is distinguished by high-quality sound and functionality. Compactness allows you to put the model on the shelf and on the floor - the choice of location depends on the acoustic characteristics of the room. The frequencies are easily adjustable, so you can adjust the sound of several speakers at once. The highlight of the model is the Standby mode, which uses a minimum of energy.

MJ ACOUSTICS REFERENCE 100 MKII

This subwoofer for the home is more expensive than the models described above, but boasts an optimal functional set and high-quality sound. High-quality sound reproduction is noted at all frequencies, in addition, it also reproduces ultra-low frequencies. In addition to good sound and small size, the model attracts attention with the presence of a control panel.

VELODYNE IMPACT-10

This subwoofer is worthy of attention for the optimal ratio of price to power and functionality. active type works without additional equipment in a wide frequency range. The maximum power is 250 W, while the device can be used in areas of any size.

We have described the 5 most popular subwoofers, on the basis of which you can create a quality

Connection Features

The subwoofer is an important component of modern acoustics, allowing you to feel every sound. Before you buy this or that model, you should find out about the parameters of the sound card on the device to which the sub will be connected. How to connect a subwoofer at home? It also depends on the type of devices. For example, a 5.1 system consisting of five speakers and a subwoofer does not dock with a laptop. You can try to connect the sub to the computer, but also only if the number of inputs on the sound card matches.

Selection Options

The task of the subwoofer is to "finish" the lower part of the sound spectrum, which ordinary speakers cannot cope with due to their low power. When choosing optimal model proceed from the following parameters:

• frequency range;
• crossover frequency;
• maximum sound pressure;
• system sensitivity;
• woofer diameter.

These are key terms for subwoofers, but it is their knowledge that guarantees the correct choice of component for the speaker system.

Features of connecting a car subwoofer

Very often there are situations when owners sell their car, and use the subwoofer from it to create a home speaker system. How to connect a car subwoofer at home so that it works stably? To create such a device, you need a power supply and speakers, as well as the subwoofer itself. It is easiest to take as a power supply for an auto amplifier computer block power supply, which has all the necessary characteristics. The steps for connecting the sub to the power supply are as follows:

• yellow wires are connected to the terminals on the car amplifier (“-” - to the GND terminal, “+” - to + 12V);
• a special input with a blue wire is used to connect a subwoofer, an external amplifier;
• The sound source can be a conventional MP3 player with an adapter.

When creating a do-it-yourself subwoofer for your home, remember that a car amplifier can draw current in excess of 40 amperes. In this case, it is advisable to use copper wires with a cross section of 6-10 mm 2 to connect it. To improve the sound, you should pay attention to the input signal level control, which is located on the amplifier panel. Thus, there are no particular problems with sound adjustment when using a car subwoofer.

How to make from scratch?

A subwoofer is a powerful addition that could well become part of a home theater system. But what if there is no money to buy ready-made equipment, but you want to enjoy high-quality sound? In this case, you can try to make a subwoofer for your home with your own hands. To do this, you need to perform a number of actions:

1. Buy speakers and a cabinet (wooden is best).
2. Calculate the dimensions of the boxes. For this you can use computer programs, in which you need to specify a number of parameters - the dimensions of the speaker and phase inverter.
3. Make parts. After the calculations, you can begin to create the details of the future subwoofer. It is best to use high quality wood, plywood: in addition to naturalness, they are ideal for a variety of processing.
4. Assemble the body. After all the details of the future device are sawn out, they need to be connected to each other. For greater reliability, the walls are most conveniently fastened with self-tapping screws.
5. Connect the speaker to the amplifier and power supply. This may require subwoofer drawings for the home, which mark all the nuances of connecting the main elements. The block diagram of the entire sound system plays an important role, which means that close attention should be paid to this side of the assembly.
6. Insert the finished and already amplified speaker into the case. Sheath it. Bring all the wires out from the back of the box through special connectors.

Everything, the subwoofer is ready for operation, you can check it. If suddenly during operation unpleasant sounds, rustling appear, it makes sense to check whether all the holes in the box are closed. They must be sealed - for this you can use glue or sealant. In any case, you can make a subwoofer for your home on your own, if you understand the diagrams and drawings.