Before you start designing and assembling the box, you need to decide on the choice of speaker. We recommend that you opt for 10-12 inch imported speakers, as they are most commonly used in car subwoofers and are the best fit. How to choose a speaker for a subwoofer, we described in detail in a previous article. The design of the box is also important: the quality and volume of bass sound depends on it.
What are subwoofer boxes?
There are several types of subwoofer boxes. Sound quality directly depends on the design of the box., which you will receive at the output. Below are the most popular types of subwoofers:
The closed box is the easiest to manufacture and design, its name speaks for itself. The woofer is housed in a sealed wooden case that improves its acoustic performance. Making a subwoofer in a car with such a case is quite simple, but it has the lowest efficiency.
A 4th order bandpass is a type of subwoofer whose enclosure is divided into chambers. The volumes of these chambers are different, in one of them there is a speaker, and in the second - a phase inverter (air duct). One of the features of this type of subwoofer is the ability of the design to limit the frequencies that the cone reproduces.
The bandpass of the 6th order differs from the 4th order by the presence of one more phase inverter and one more camera. There are two types of 6th order bandpasses - the first has one phase inverter, and the second has two (one of them is common to both cameras). This type of box is the most difficult to design, but gives the maximum efficiency.
Phase inverter - a subwoofer with a special tube in the case. It expels air and provides additional sound from the back of the speaker. In terms of manufacturing complexity and sound quality, this type is a cross between a closed box and a bandpass.
If you want to get the highest quality sound, you can opt for bandpasses. But this type of construction has many details that must be carefully designed and calculated. All this can be done with special program WinlSD, which will not only determine optimal size and the volume of the subwoofer, but will also create its 3D model, as well as calculate the dimensions of all the details.
Unfortunately, this program requires at least minimal knowledge in this area, and an ordinary motorist is unlikely to be able to do everything right the first time. Moreover, in order for the program to work correctly, it needs some speaker parameters, which are also not known to everyone. If you do not plan to take part in auto-sound competitions, we advise you to discard bandpasses.
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A phase inverter will be the most optimal solution for a homemade subwoofer. This type of box is good because the tube (phase inverter) allows you to better reproduce the lowest frequencies. In fact, this is an additional sound source that contributes to the sound of the subwoofer and increases efficiency.
What materials do we need to build a subwoofer?
The material for the manufacture of the subwoofer box must be durable, dense and well isolate the sound. For this multilayer plywood or chipboard is perfect. The main advantages of these materials are affordable price and ease of processing. They are quite durable and provide good sound insulation. We will be making a subwoofer from 30mm plywood.
To make a box for a subwoofer, we need:
- Self-tapping screws for wood (about 50-55 mm, 100 pieces)
- Soundproofing material (shumka)
- Drill and screwdriver (or screwdriver)
- electric jigsaw
- Liquid Nails
- sealant
- PVA glue
- Carpet, about 3 meters
- Klemnik
Subwoofer box drawings
In this article, we will make a box for a subwoofer with a 12-inch speaker. The recommended volume of the box for one 10-12 inch speaker is 40-50 liters. Calculating a box for a subwoofer is not difficult, here is an approximate diagram with panel sizes. 
It is worth paying attention to the minimum distance from the walls of the case to the speaker. It, like the volume of the entire box, is calculated from the inner surface.
Video instruction: how to make a drawing for a subwoofer yourself
We assemble a box for a subwoofer with our own hands
You can start assembling. We use a 12" Lanzar VW-124 speaker. 
Its diameter is 30 cm, and the first thing to do is to cut a hole for the speaker. The minimum distance from the center of the diffuser to the wall of the subwoofer is 20 cm. We measured 23 cm (20 cm + 3 cm plywood width) from the edge of the panel and cut a hole with a jigsaw. Next, we cut a hole for the phase inverter slot, in our example it has a size of 35 * 5 cm. 
Instead of a slot, you can use a classic air duct - a tube. Now we assemble the bass-reflex slot and attach it to the front panel of the subwoofer. We pass along the joints with liquid nails and twist with self-tapping screws. 
It is important to tighten the screws very tightly so as not to leave voids. They will create resonant vibrations that will ruin the sound of the subwoofer.
Next, we assemble the side walls of the box, having previously lubricated them with liquid nails, and tighten them tightly with self-tapping screws. 
On the back cover of the box, you need to cut a small hole for the terminal block. We connect all parts of the body. We make sure that we correctly cut out and fastened all the parts. 
Insert speaker. Look, we love. 
Let's move on to interior decoration boxes. The first thing to do is to glue all the joints and cracks with epoxy glue or sealant. Next, using PVA glue, we glue soundproofing material on the entire inner surface of the box. 
Now we cover the entire outer plane of the box with a carpet, including the phase inverter slot. You can attach it with epoxy glue or with a furniture stapler. 
Next, insert and tightly fasten the speaker. The subwoofer is almost ready, it remains only to stretch the wires from the speaker to the terminal block and connect the amplifier. 
We bought an amplifier, but you can also make it yourself. This is quite difficult, as it requires knowledge and practice in the field of radio engineering. You can also use ready-made kits and circuits for radio amateurs, like Master-KIT, and assemble the amplifier yourself. The only thing requirement for the amplifier - its maximum power must be less than the maximum power of the speaker.
See also a video report on the manufacture of a homemade subwoofer for 2 speakers
We make a stealth subwoofer with our own hands
Tired of carrying a huge box in the trunk? Then the stealth subwoofer is just right for you. This unique case type is more practical than the classic drawer. It does not stand in a square box in the middle of the trunk and takes less space. Often, stealth is installed in the inner part of the wing, sometimes in a niche instead of a spare wheel. The minimum volume of the box that requires a 10-12 inch speaker for normal operation is 18 liters.
To make a passive stealth subwoofer, we need:
- subwoofer;
- protective grille and socket for connection to the amplifier;
- wire for connecting the speaker to the outlet;
- multilayer plywood or chipboard (thickness 20 mm);
- a small piece of fiberboard;
- epoxy adhesive;
- tassel;
- fiberglass;
- mounting tape;
- polyethylene film;
- wood screws;
- drill, jigsaw.
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After choosing a place where the stealth will be installed, we free the trunk and proceed to the manufacture of the case. You can remove the trunk lining at the location where the subwoofer will be installed to place it even closer to the fender. First of all, lay a plastic film on the trunk floor. It performs two functions at once: it protects the trunk lining from epoxy glue and allows us to make a mount to which we will screw the bottom of the subwoofer. Next, glue inside wings with mounting tape in two layers. 
We cut the fiberglass into small pieces, approximately 20x20 cm. We put pieces of fiberglass on the masking tape and glue it with epoxy glue. It is better to overlap the fiberglass so that there are no obvious joints and seams. 
We sculpt layers of fiberglass on top of each other, simultaneously lubricating them with epoxy glue, until the sheet thickness reaches 10 mm (about 4-5 layers). 
The material will harden for about 12 hours. To speed up the process, you can use a lamp. Now we cut out the bottom of the subwoofer and glue it to our case. The joint is treated with sealant or glued with epoxy. 
In this particular case, the shape must be adjusted to fit the trunk hinges so that our homemade subwoofer does not prevent it from closing. After we cut off all the excess, we cut out the side walls and the top cover from the chipboard. We make the rounded part of plywood, we did it “by eye”. 
To make it easier for plywood to give a rounded shape, it must first be wetted, shaped into the desired shape, fixed and allowed to dry.
Chipboard sheets must be glued with epoxy glue or sealant, and then fastened with self-tapping screws. We also glue the fiberglass box with epoxy resin, and when it dries, we fasten it with self-tapping screws. 
For better sealing, glue the seams again. We applied another layer of epoxy and sanded down the structure to give the glue a better grip. 
Next, we can measure the front panel and cut it out. Using a jigsaw, cut out a circle for the speaker. In order to securely attach the front panel to the case, you need to tighten it with self-tapping screws from all sides. That is, on the entire inside of the panel, you need to install the bars, at a distance slightly greater than the thickness of the plywood (in our case, we attached the bars at a distance of about 25 mm from the edge of the panel). Thanks to this, we will be able to fix the front part from above, below, on the sides, and most importantly - securely attach it to the rounded element.
Cut a hole in the end for the outlet. 
In the end, it was decided to add two more layers of fiberglass and epoxy glue to the curved part of the housing for the stealth subwoofer. 
We carry out the final assembly: we install the socket and connect the speaker to it, but we do not fasten it yet. Further there are two options - paint the subwoofer, or cover it with carpet. Painting is a little more difficult, as you must first level the surface. To do this, we used a universal putty. 
Align everything with sandpaper, primer and paint. Subwoofer is ready!
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The Matrex public and business center in Skolkovo will rightfully become one of the new symbols of Moscow, not only in the architectural, but also in the technical aspect. The latest multimedia systems and solutions ahead of time make Matrex unique.
The Matrex public and business center in Skolkovo will rightfully become one of the new symbols of Moscow, not only in the architectural, but also in the technical aspect. The latest multimedia systems and solutions ahead of time make Matrex unique.
Everything I know, I learned on my own. Read, observe, try, experiment, make mistakes, redo. Nobody taught me. At that time there were no special educational institutions in which they would teach how to work with lighting equipment. Actually, I don't think it can be learned. To become a lighting designer, you need to have something like this “inside” from the very beginning. You can learn to work with the remote control, programming, you can learn everything specifications but you can't learn how to create.
The Matrex public and business center in Skolkovo will rightfully become one of the new symbols of Moscow, not only in the architectural, but also in the technical aspect. The latest multimedia systems and solutions ahead of time make Matrex unique.
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Horn acoustics
Horn acoustics has always been more expensive than usual. And it is not surprising that the most ardent fans of such acoustics are those users who once owned traditional speakers.
There is nothing surprising in this. A sophisticated listener will always appreciate the overall harmony, integrity of perception and naturalness of sound.
The user himself likes horn acoustics in view of their musicality and ability to capture the listener.
What it is
Modern audio equipment is capable of reproducing the entire range of required frequencies. This is enough to transmit musical compositions, but not enough to create a sense of the presence of the listener.
As any music lover will tell you, there is something that is responsible for the transmission of not just music, melody, but also for the transmission of the performer's emotions. Horn acoustics just perfectly copes with this matter.
Horn acoustics are not designed like conventional ones. The speaker (see) in it is not quite large in size and it joins the horn, which increases the volume of its sound.
This can be compared with the case when a person, in order to shout to an interlocutor at a great distance, folds his hands with a mouthpiece.
Note. If you are thinking about purchasing horn speakers in your car, we hasten to warn you: the difference between good and bad horn speakers is very significant than is observed in traditional versions.
Cheap horn acoustics made by an unscrupulous manufacturer cannot in any way act as a comparison. It was these cheap options that gave rise to rumors that supposedly horn acoustics are good, but the sound in them is colored.
As for high-quality horn speakers, they are always expensive. They always use Alnico magnets and exotic metal diaphragms.
Horn acoustics are always assembled according to strict tolerances and dimensions. In a word, such a production technology cannot imply any compromises and cost reduction.
Let's give examples. A two-inch TAD compression driver, used in all Cesaro horn acoustics, costs about 1,000 euros. At the same time, the most expensive tweeter to date is the beryllium-diaphragm Scan Speke, which only costs about $600.
Horn acoustics for cars are always unique products produced in series. The names of some in gold letters are inscribed in the history of car audio.
For example, this is the Japanese horn acoustics Maxonik, which has been produced since 1932. Today Maxonic always presents high-tech products.
When creating, expensive technologies are always used with the use of magnetic systems in emitters.
Story
So:
- It will be interesting to know that the very first loudspeakers in the world were horn-type. They appeared in the 20s of the last century.
The technology of creation was the only one and then they simply did not know how to make other acoustic systems; - Ten years later, speakers appear that are already similar to today's versions of traditional acoustics. They immediately gained great popularity, but forgot about horn acoustics.
Then it was mistakenly believed that the ideal place for horn acoustics would be the sounding of large spaces, and for pleasant listening to music, it is simply not suitable; - Another ten years pass and the famous American engineer creates a completely new design of horn acoustics. It was Paul Klipsch (that was the name of the engineer) who proved that horn acoustics would make it possible to reproduce musical compositions with very high quality.
Note. It was then that the engineer founded a company producing horn acoustics, which to this day is a world leader. The company was called Klipsch, and speakers of this type were called Klipsch.
- Interestingly, music lovers immediately "figured out" that the "clips" reproduce music in a special way. Since that time, horn acoustics have become the choice of a rather narrow circle of connoisseurs of real music;
- The second half of the last century was marked by the appearance of completely new carriers. In addition, there are new developments and new approaches for processing and amplifying the audio signal;
- Finally, having reached the apogee of modernization and improvement, people began to realize that the sound had not been able to give "liveness". And then the eyes of many turned to horn acoustics, which began a real boom about three years ago.
The magical sound of horn systems
So:
- The fact that horn acoustics sounds in a special way is not difficult to verify. And for such a sound there are all the prerequisites. Firstly, horn acoustics are highly sensitive. This makes it possible to reproduce the most subtle nuances, convey the emotions of the performer;
- Secondly, horn speakers produce sound waves that are more "natural" in nature compared to the air vibrations coming out of traditional speakers;
- Horn acoustics can reproduce low frequencies, but its dimensions depend on this. In other words, the lower frequencies you have to reproduce, the larger the size of the horn speaker should be.
Note. It is for this reason that horn acoustics are used for the most part for reproducing midrange and treble, but if you choose larger speakers for yourself, then bass will be reproduced at the highest level.
- And that is not all. Low frequencies will be reproduced not just like that, but at the highest level. True, only the most subtle connoisseurs of sound can distinguish the difference in reproduction.
Note. Interestingly, in recent times quite often there are speakers where only the tweeters are made in the form of a horn. For example, the same speakers of the Clipsch Reference series are made according to this model.
- The high frequencies reproduced by horn speakers sound much louder. Needless to say, the HF quality is better than when using conventional tweeters.
Recently, among the manufacturers of horn acoustics, I would like to single out the Italian company Zingali separately. The engineers of this company have created an original horn radiator that simultaneously reproduces midrange and high frequencies, and at the same time looks beautiful.
Horn acoustics in a car
Needless to say, all traditional automotive speakers do not allow you to achieve High Quality sound. It's not about anything, but in a cramped cabin.
Here the horn ones will give a chance to significantly exalt the sound, create the effect of presence (as if you are sitting in a studio or at a concert). The explanation can be simple: the horn increases the distance over which sound waves propagate, while increasing the density of sound and giving a characteristic melody.
Technical solutions for placing such acoustics in a car can be different:
- So, the most popular way is to install the loudspeaker in front, frontally on the wall of the case, inside which the main waveguide is formed. It has an outlet to the outside;
- Another option involves a horn system, where there is a woofer. It is placed in a separate building. The same fate is followed by tweeters and midrange speakers, which are also placed in the corresponding case separately from each other.
Advantages and disadvantages of horn acoustics
This concludes our review of horn acoustic systems. Recently, they have been increasingly installed in cars with their own hands, using step by step instructions, useful videos reviews, drawings and photo - materials.
The price of good horn acoustics is very high, but this will not stop ardent music lovers.
In this article, we will consider in detail how to make a subwoofer with your own hands, if there is no professional knowledge in the field of electroacoustics and there is no desire to use previously unknown and incomprehensible circuits, although of course you still have to make some measurements.
What is a subwoofer and what is it used for?
A subwoofer is popularly called simply a subwoofer, and if you translate this word literally, it sounds quite funny - a subwoofer. In fact, this is a real bass speaker, characterized by low frequency, designed in a special box with an extremely complex device.
Today, if you look at a photo of a subwoofer with your own hands, you can see that they are used in a huge number of very different places, ranging from simple everyday situations when it is installed at home and ending with the fact that today many people use subwoofers in their cars.
If you can find a good drawing of a subwoofer and make it right, then you can definitely take on almost any complexity of speakers, since bass reproduction is one of the most difficult moments in the world of electroacoustics.
It is only important that the subwoofer circuit fully meets your idea of \u200b\u200bideal acoustics.
A little about bass
Reproducing different basses is, in principle, a rather difficult process. In general, the low-frequency section of absolutely any spectrum of available sound waves differs depending on its psycho-physiological strong impact on several areas.
In order not to make a mistake in choosing a bass, really high-quality speaker, and subsequently the box for the subwoofer was completed quickly enough, first of all, it is necessary to mean their key importance and the corresponding boundaries.
Depth
For various types of wind organs in halls specially renovated for musical instruments significant influence the sub-bass has an impact on the tone of the sound. It is for the sounds of nature and various man-made disasters, such as unexpected explosions, that quite strong sub-bass components are characteristic.
It is worth noting that most people either do not hear subbass at all, or they hear, but not well enough. For example, if we filter out the fundamentally different sounds of a nuclear explosion and a strong hurricane, like a tornado in the tropics from everything except for sub-basses, then we can say with absolute certainty that hardly any of the listeners will be able to understand that is actually happening.
It is for this reason that almost everyone optimizes a subwoofer for the home exclusively for midbass.
How to choose a speaker?
When choosing, you should definitely pay attention to the fact that a full calculation of the entire acoustic design is always made only according to known parameters Thiel-Small.
When creating a good subwoofer on your own, it is only important to take into account the absolute quality factor of the head precisely at its main resonant frequency. This is due to the fact that it is used to select the ideal option for future acoustic design.
Auto subwoofers
If you are interested in car subwoofers, then in this case you should definitely keep in mind that they are most often installed either directly under the driver's seat or in the trunk compartment.
When placed in the second option, the auto subwoofer can take up quite a lot of usable space, so it is not used so often. However, even if the subwoofer is placed under the seat, there are some risks associated, for example, with the fact that it is quite easy to damage it with your feet in this case.
It is worth paying special attention to everything else important point, which consists in the fact that in a fairly cramped interior of the car one cannot do without the obligatory effect of masking various noises.
It is for this reason that almost all car subwoofers are optimized primarily for sub-bass.
In conclusion, it is worth noting that, in principle, anyone can make an amplifier for a subwoofer on their own, and this will be quite a fun activity, useful not only for developing skills, but also for the mind.
Note!
DIY subwoofer photo
Note!
Modern music and special effects in movies (such as explosions in movie soundtracks) contain a lot of low frequencies. While full-range speakers can have a fairly full range of frequencies, they are complemented by subwoofers that can really reproduce low frequencies clearly, which is especially true for bass-heavy music, such as EDM (electronic dance music) or reggae.
Placing regular speakers is usually a relatively simple matter, but placing and configuring subs has several options and can be more of a challenge. Let's start with the basics.
A subwoofer is a specialized cabinet that reproduces the extreme, lower end of the frequency range. Studio or home theater models can operate from 20 to 250 Hz, in sound reinforcement subs typically operate from 30 to 120 Hz, with a crossover point of 80 to 100 Hz. They can be passive, powered by external amplifiers and processors, or active, with built-in amplification and processing.
In smaller systems, the signal to the subs and the main speakers is sent from one main output of the console, while larger setups can only receive low-frequency content from low-frequency instruments, such as a bass drum, bass guitar, or even a bass vocalist . In this case, the signal for the sub is sent to amplification through a separate console output (aux, matrix or mono bus). This helps to clean up the "muddy" sound of the lower end of the range, because the open mics on the stage, which "suck" the noise from the stage, and which may be out of phase with each other, are eliminated from the low-frequency signal.
There are several various types subwoofers, each design is a compromise between bandwidth, efficiency, size and price. Designs may use one or more speakers arranged in a variety of configurations, including:
Sealed body.
The speaker(s) is(are) installed in a sealed enclosure. Although this design works out transients well, compared to a ventilated case, the efficiency is low, and reproduction of the lowest frequencies is quite problematic, especially on high levels volume. One notable exception is a specific design that uses its own processing electronics to reproduce low frequencies (down to 20 Hz).
Bass Reflex / Ventilated Enclosure / Bass Reflex Enclosure.
The most common type of subwoofer design in sound reinforcement, the "bass reflex" has the speaker(s) mounted in a box that also has one or more air vents. The vent (or port) is sized and long enough to ensure that the sound coming from the back of the speaker as it exits the box is in phase with the sound coming from the front. The advantages of a bass reflex over a sealed design are many, including: extended low-frequency response, increased power, and increased sound pressure.
However, these benefits come along with increased cost, big size housing and weight, and slow transient response. It is also necessary to use an additional low-cut filter, below the tuning frequency, to protect the speaker suspension system from damage at high levels.
Bandpass.
In this design, one (or more) speaker is placed in a resonator chamber, which may be closed or ventilated, and plays into a second ventilated chamber located in front of the box exit. Passing through these tuned chambers, the sound is limited in frequency range, but the output is increased within the frequencies specified by the chambers, along with the reduction of upper harmonics.
The disadvantage is that placing a second resonant chamber in front of the driver increases the size of the cabinet.
Loaded speaker. As the name suggests, the speaker is housed in a closed (sometimes ventilated) chamber, the output of which is directed through a horn. The horn increases speaker output and can also improve directivity, depending on the length and area of the horn's outlet (the part that goes out). Since low frequencies require a large horn, designers tend to bend, fold, or fold the horn into the cabinet, resulting in a more reasonable box size.
DrawingLAB Sub, subwoofer design "loaded horn".
The horn design is supposed to increase the level compared to the bass reflex design, but sometimes it doesn't reproduce the lowest frequencies very well because a substantial horn size is needed to handle those long wavelengths. However, they can be stacked in groups for additional bass extension. The large size and weight of these cases tends to limit their use for large events.
Back loaded horn.
The speaker is placed at the exit of the horn, one side is directed into the horn, the other - to the exit of the horn. Mounting the speaker in this location reduces the required speaker travel compared to a normally loaded horn, resulting in less distortion and more output. These benefits come along with an increase in the cost, size, and weight of subs. However, the results can be very good, especially in problematic acoustic environments.
Cardioid.
This design allows more exit from the front of the drawer and less from the back. This is usually achieved by adding another speaker at the back of the cabinet and changing their phase relationship and/or output arrival time with respect to the front speaker, helping to null out the rear sound waves.
The cardioid design focuses low-frequency energy on the audience, reducing unwanted reflections and stage noise. These advantages come with more cost and weight, and additional amplification and processing is also required if the subs are passive. However, the results can be very good, especially in problematic acoustic environments.
hybrid designs.
They use a combination of different approaches within the same body. For example, I recently came across one configuration with two speakers sharing a ventilated chamber. One front-firing speaker stands straight, and the second one is at a 90-degree angle, and radiates into the second ventilated chamber.
Also on the market is a cardioid passive subwoofer with two drivers: an 18-inch bass reflex configuration and a 15-inch folded horn.
Obviously, there is a lot to discuss when it comes to subwoofers, and what I have presented here is intended as an example, just as a canvas ground on which any picture can be painted. A good understanding of how subs work and interact is well worth your time, and delivering bass energy with maximum impact and control is one of the keys to a successful sound reinforcement experience.
Craig Learman
