Making a podium for a subwoofer with your own hands

The box is one of the most important functional parts of a woofer. Without this irreplaceable design element, the subwoofer will simply drive air, lowering the percentage of the current efficiency. In addition, the box helps to neatly hide the useful part of the audio system, without any sacrifice to its overall design.

The meaning of the correct calculation of such a product lies in the need to design the design of the speakers, which will subsequently suit you not only with the musical qualities of the resulting system, but also with its appearance. This guide contains all the useful tips and detailed recommendations that answer the question of how to make a subwoofer with your own hands.

Types of boxes

According to the design features, acoustic design is divided into several main types:

1. Closed.
2. Bass reflex.
3. Bandpass loudspeaker.

A closed box is the most popular design option for a subwoofer. Most audio system owners prefer this type due to the simplicity of such products. Sound vibrations arising in a closed structure are isolated from the environment, and the damped frequency is damped against the walls, creating a volumetric effect. The main disadvantage of closed boxes is due to the energy distribution factor: the forces acting on the internal part of the design system contribute to heat transfer, which negatively affects the quality parameters of the speaker.

The role of an active subwoofer

Installing an active subwoofer in a car

Typically active subwoofers perform the following main role:

• An audio system of the highest quality is capable of playing frequencies that have a different range.
• The diffuser area is quite large, due to which it also becomes possible to reproduce low frequencies of sound.
• Also, a subwoofer (see How to make a subwoofer: practical tips) may also be needed when some moments played by the device lose their attractiveness.

Note: in this case, a passive subwoofer will definitely not cope (unless you carry out thorough special training, which only a professional can do), so you need to use only an active one.

Where to install

Installing an active subwoofer on a car

You can install the radio in any convenient place in the car. But at the same time we will consider the most popular of them:

• Trunk. This is because this is where it is easiest to install a subwoofer, since there is usually a lot of free space in the trunk. However, this will cause the sound frequency to become lower. However, once you find a suitable location for the speakers, you can easily adjust the quality of the sound produced.

Sub in the trunk

• In some cases, subwoofers are installed directly in the front panel. Of course, the sound produced will be of high quality. However, such a process will be more complex from a technical point of view.

Note: usually those owners who install subs here are true fans of high-quality sound and who are willing to do almost anything to get maximum sound.

• Subwoofers are often installed under the driver or front passenger seat.

Tools and materials

Before starting work on making a subwoofer box with your own hands, you should decide on the set of tools and materials to use. You also need to perform certain calculations, draw drawings, and also create your own step-by-step guide, without fail following it in the future.

Various types of materials can be used to make the design system for the woofer. Products created by the hands of folk craftsmen are usually made of plywood, chipboard or MDF. In the more professional market, boxes made of transparent plastic or glass are in demand, which allow you to give a modern look to the finished structure. However, audio systems encased in wood, in addition to their decent appearance, receive significant bonuses in terms of quality sound characteristics. Before starting work, it is important to decide on the location where the homemade box will be installed.

In our case, the procedure for making a subwoofer box with your own hands will require the following tools and materials:

• Speaker 10 x 12;
• Protective grilles and sockets;
• Cable set;
• Multilayer plywood 20mm thick;
• Fiberboard sheet;
• Epoxy adhesive;
• Brush;
• Fiberglass;
• Construction or regular tape;
• Wood screws;
• Hand drill;
• Jigsaw.

The entire set can be purchased at a large hardware store - literally in one go.

Active subwoofer housing and its types

The device of active subwoofers

The housing of this speaker creates a unique acoustic design. However, some devices require a variety of designs. Active subwoofers can be installed in the following boxes:

• Closed box. It is quite simple to make. In this case, connecting a subwoofer with this design is carried out in a few simple steps. During installation, it is practically impossible to make any mistakes.

Note: you can make a closed enclosure for a subwoofer with your own hands.

• Strip box.
• Box with bass reflex. This is a box with a port of a certain length. The main advantage is that it can be used to create any pressure in the system. However, to install such a device, you must have a lot of knowledge and experience.

The main requirement for any type of box is that it must be as airtight as possible so that the subwoofer itself is effectively protected from external conditions. The manufacturer must take into account that the highest quality surface should be the one that comes into direct contact with the speaker. After all, there are usually gaps and cracks on the uneven surface, which can ruin all efforts to install the device.

How to make a subwoofer box

Despite the apparent complexity, the work of making a box for a subwoofer is a fairly simple task that even a person without any specific skills can handle.

Before you start making the design for the woofer, you need to find and prepare all the necessary materials, tools and drawings. By following all the recommendations and advice, you will cope with the task without any problems.

How to calculate a box

Calculation of the subwoofer box should be done using specialized software. Similar calculation calculators suitable for this task include the WinISD or JBLSpeakershop packages.

After installing and launching the program, you will see several fields for entering information. You need to insert the initial data into the empty lines - based on them, the calculator will calculate all the necessary values. Calculating the subwoofer housing is a very important stage, on the quality of which all subsequent work depends.

How to assemble

The procedure for making a box for a low-frequency speaker is divided into several stages. You should carefully read each of them before starting work: in this way, you will save yourself from any errors or unforeseen circumstances.

• The surfaces towards which the head will look should be made double, using several sheets of material. A small hole should be made in the first sheet, recessing the head inside the structure;
• In order to glue the sheets together, you need to use epoxy glue and screws. Fasteners should be placed every two to three centimeters of the product plane;
• The walls are connected to the base of the box using furniture screws. Their presence makes the structure much stronger;
• The three-sided strip located in the inner part of the case must be glued in all corners. Thus, we increase the strength of the structure and prevent the appearance of deformed areas.

Blueprints

The outer woofer box design diagram is a handy information sheet that simplifies the assembly process of the product. Since in our case we are considering the procedure for creating a box for a 12-inch subwoofer, the optimal volume of the workpiece should vary from 40 to 50 liters. The drawing is created using the following dimensions:

• Width – 700mm;
• Height – 450mm;
• Depth – 260mm;
• Front and rear panels – 700/450mm;
• Left and right panels – 450/260mm;
• Top and bottom panels – 750/260mm.

According to the specified dimensions, you can draw a structural drawing with which you can assemble the finished product.

How to choose speakers

After completing the assembly of the case, you should take care of the selection and installation of loudspeakers. The speakers included in the audio system must have excellent characteristics in terms of reproducing low-frequency waves by converting an electrical impulse into air vibrations. The quality of the speaker depends on several quantitative indicators, the exact values ​​of which can be found in the operating documents for the device:

• Resonance frequency;
• Quality factor;
• Equivalent volume.

Good models of acoustic loudspeakers have a resonant frequency of 20-50Hz. Quality factor is an indicator indicating how well the resonant vibrations of the diaphragm element are damped. Equivalent volume is the volume of air inside the structure, independent of the overall dimensions of the speaker. When choosing a speaker, try to choose a device with high performance.

How to install

The procedure for installing a woofer is an extremely simple job that can be performed even by a person who does not have professional knowledge in the relevant field. You can choose the following as the main installation location for the audio system:

• Car interior trim;

• Level of the luggage compartment floor;

• A separate place, the dimensions of which correspond to the dimensions of the system;
• A subwoofer that does not have an impressive size can be placed under the car seats.

Making a podium for a subwoofer with your own hands

After making the podiums, it was time to think about the subwoofer. Of course, you could just buy a cabinet sub, but for me this is too easy. And in general, if you want to know my opinion, a ready-made box for a real man should be made only once, and to completely different music...

Technology selection

Having carefully read all the recommendations, I decided to build a “stealth” type box (hidden, irregularly shaped, repeating the shape of part of the trunk) from fiberglass and carbon fiber with plywood walls.

Materials and tools

The basic materials I needed were:

• Epoxy, 9 bottles of 300 g, manufactured in Dzerzhinsk.
• Fiberglass fabric 0.3 mm thick (most likely industrial), without wax, about 2.5 square meters. m.
• Carbon tape with a thickness of 0.1 mm and a width of 0.4 m is about 4 m.
• A sheet of plywood 9 mm - about 1.8 square meters. m.
• Polyester putty with fiberglass - 150 g.
• And also sandpaper, nails, screws, paper tape, plasticine, Matson aerosol paint, Moment glue, hot melt glue, carpet (carpet).

I didn’t have a jigsaw then, so I used regular saws - wide and narrow, also an electric drill, a Black & Decker hair dryer, metal scissors, a knife-cutter and also a hammer...

Sticker

I decided to place the subwoofer on the left in the trunk - there is less distance to the battery and more space in the niche due to the lack of a gas tank neck. I also planned to use the space that is located behind the plastic plug, and, as it turned out, it was not in vain, it is an additional 5 liters of volume. To begin with, I prepared the surfaces: I sealed everything with paper tape, including the plastic sidewall. Then, using cardboard, tape and plasticine, I made a shell (ends) around the cutout flush with the edges, having previously glued a piece of 8 mm foam to the inner surface of the rear wing. This is so that the finished form does not rest against the wing from the inside. Here it is important to ensure that the side cardboard walls are positioned at a slight angle, otherwise the cast will be impossible to pull out of the hole. Then, using the same plasticine, I slightly adjusted the resulting matrix to give smoother contours to the cast. I heated the plasticine with a hairdryer, otherwise it was very difficult.

The surface prepared in this way was generously smeared with lithol and began gluing. I laid the fiberglass fabric overlapping, in strips about 15 cm wide, slightly heating them with a hairdryer and squeezing out the bubbles. I did not smear the surface with resin (it is in lithol), but pre-impregnated the strips. At this stage, I didn’t have a very clear idea of ​​the future shape of the box, so I covered a obviously large area.

Epoxy cures slowly at low temperatures, so I had to find a warm garage to cure the mold. It turned out to be much easier than I expected, and after spending the night in the huge, warm factory garage, I solemnly tore out the resulting cast, albeit with some effort...

Walls

I figured out the number, shape and size of the side walls on the spot, cutting them out of cardboard and fastening them with hot melt glue (sold in the form of rods, melted with a soldering iron or inserted into a special “gun”). But at this stage there is one important problem for which I found (I’m proud of myself!) a non-trivial solution.

It was not possible to take a photo of the form before pasting. The fiberglass fabric is laid in one overlapping layer, paper tape and plasticine are visible through it

The cast stuck perfectly to the wooden wall in the most uneven area. If you look closely, you can see traces of carnations around the perimeter

This cutout is for the standard rear speaker. The same 9 mm plywood, epoxy and small nails were used

Top wall. The cutout for the speaker does not have a second layer of plywood, but then I glued a stiffener on it

How to estimate the volume of a box? I never found a ready answer, I had to come up with one. The box from the speaker held 20 liters, so I cut it out of cardboard by eye and fastened the walls together to make one and a half boxes. You can more accurately measure the volume only with the help of bulk or liquid substances... Cereals (30 liters of cereals - oh-oh!), sand, expanded clay or foam balls may also be suitable... We are not talking about water yet - the design is not airtight in principle. But a fresh solution came naturally, but not right away: I poured 6 liters of water into regular garbage bags, tied them up and simply threw them into the mock-up box! Although the structure almost crumbled due to the gravity of the water, I achieved my goal...

Then I cut out the walls from 9 mm plywood, trying to take into account the reduction in volume in the future: the thickness of the walls, the volume of bars and stiffeners, epoxy (9 bottles of 300 g each), fiberglass, etc. I fastened the new walls with hot glue and took measurements a second time. If there are doubts about the correctness of the measurements, then you can make the width of the walls with a margin and cut off the excess later, when sufficient strength has been gained. The top wall had to be built with a cutout for the speaker in the standard place of the trim. This is how I plan to organize the rear audio.

The bottom and part of the back wall are glued in one piece. It can be seen that in the “sandwich” the layers of carbon tape are narrower than the fiberglass at the edges. Only half the thickness has been gained so far

The screws are located somewhat cunningly - so that they do not “meet” inside the block. For better recessing of the heads, the place was pre-drilled with a large drill

Directly ahead is the wall adjacent to the wheel arch. It had to be strengthened, plus a stiffening rib

Wooden strapping in one layer, the bottom is not yet thoroughly glued. The cast had to be sanded a little from the inside

The drawer and top lid are ready to be assembled. I glued strips of plywood along the edges of the walls - slightly increasing the width of the walls and, accordingly, the volume of the box

Next, I fastened the walls together using screws (self-tapping screws), blocks and epoxy. It is better to cut the bars from hard wood: beech, oak, birch. Places for screws (I took 4 x

25 mm) marked and pre-drilled with a drill 0.5-0.75 of the screw diameter, otherwise the block would split. I would like to add that I fastened the side walls together without separating the back, in order to constantly control the position of the wooden part relative to the fiberglass. That is, he broke the temporary adhesive connection, put the block in place and again fixed the area with hot glue. When the wooden frame had dried, I thoroughly glued the back wall to it with epoxy, nailing it with glazing beads (small ones) around the perimeter for a complete fit. After that, I cut off the excess cast and pulled out these nails here and there. When joining, I filled all the cracks with a mixture of resin and sawdust. The initial form was ready. Even at this stage, the box turned out to be completely sealed, so I measured the volume with water, without the bags...

Strengthening

To increase the rigidity of the wooden walls, it was enough to simply nail and glue another layer of plywood. But at my own peril and risk, I complicated my task a little and used a composite material - a “sandwich”. Three layers of carbon fiber with resin were sandwiched between two plywood walls, and the fibers were located lengthwise - across - lengthwise. I decided to drill out an additional wall and thus create a “honeycomb” structure. It seems to me that these holes do not reduce the overall rigidity of the structure, but significantly improve the damping of the walls. And besides, in total this is an additional 2 liters of volume, I calculated. It is quite possible that these holes are a controversial issue. Here I am not 100% sure of the correctness of my actions, but the tests showed good results...

Another thing is to increase the strength of the fiberglass part of the box. The optimal solution turned out to be the use of a similar “sandwich”. Only now three or four layers of carbon fiber were placed between layers of fiberglass. I carefully made such a “sandwich” on a smooth substrate (ideally on a piece of thick glass), thoroughly impregnating each layer with resin. Then I glued it inside the cast. First, I lubricated the surface with epoxy and heated the already laid “sandwich” a little with a hairdryer (the resin softened), carefully leveled it, squeezing out bubbles, and then heated it with a hairdryer even harder. After such actions, the freshly attached “sandwich” “rose”—hardened a little. Thus, it is quite possible to gain hardness layer by layer without waiting for the fresh “sandwiches” to completely polymerize.

Using this scheme, I gained a total thickness of 8-10 layers, overlapping the pieces and focusing on areas with the largest area. I also tried to ensure that the “sandwich” would grip the plywood walls a little. The form was glued quite smoothly, so the surface was practically not sanded between layers. Carbon fiber has a high modulus of rigidity, so its use greatly simplifies the task. You can, of course, do without it, but then the number of layers of fiberglass will have to be increased... And one more thing: the composite will be much stronger if it dries under a load, and not just like that. I don’t have a vacuum unit, I didn’t use pressure, but pressing the fiberglass with a bag of sand probably wouldn’t be a bad idea...

Stiffening ribs and top cover

The structure became stronger and stronger. I tried jumping on the box with all my might, but it did not produce any deformation. Nevertheless, I installed stiffeners (spacers). Jumping is jumping, and bass is serious business.

In the photo, some of the holes are filled with putty, but not sanded yet. Inside the box you can see the stiffening ribs and the wire to the speaker

Back view. This appendix fits into a hole in the fender inside the trunk. Spray painted in one and a half layers. At the bottom left you can see two columns - these are terminals

Reber cut out three pieces - from the same plywood, 3-4 cm wide. Of course, it was not so easy to repeat the relief of the fiberglass surface “close to the text”, but I didn’t try too hard: fiberglass will write off everything... I attached the ribs with nails to the wooden walls, filled the gaps between them and the cast with a mixture of resin and sawdust, and then laid strips of fiberglass at the joints. I glued a beech block to the bottom of the niche, sealing it on top with a piece of fiberglass. Well, now the strength has definitely reached o.

The top cover was also cut out of plywood. Between two 9-mm blanks I sandwiched a couple of layers of carbon fiber and a layer of fiberglass with resin, fastened the plywood with nails and pressed it with a weight. I cut out the hole for the speaker in advance, and glued and nailed an additional ring to the dried composite structure. It adds a little rigidity to the cover, and the speaker mounting screws will hold more firmly due to a longer path in the wood...

After checking the surfaces, I solemnly glued the lid to the box, screwing it tightly with screws. Small irregularities and screw heads were puttied and sanded. I also puttyed the fiberglass part of the box, but only large shells - it makes no sense to reduce the surface to “zero”: who will appreciate it, but it does not affect the rigidity.

The inside and outside of the box was painted with matte black paint, although experts recommend treating the interior with anti-corrosion agent in aerosol packaging. I also glued 10mm foam rubber onto the Moment glue from the inside for better damping of the walls. On the outside, part of the box was draped with carpet (carpet), using the same “Moment”.

I bought universal terminals - both for a plug and just for a bare wire. I drilled holes in the side wall and screwed them in place with sealant. The wire to the speaker was shorter and thicker, 4 sq. mm, I soldered and insulated the contact points.

Sealing the speaker

Incorrect pairing of the dynamic head and the box (especially for the sound box) can easily nullify all the painstaking work. Of course, there are special pads made of porous material designed specifically for placing under the rim of the speaker. You can even glue the speaker to the housing with sealant. But how to peel it off later? I used a simple and reliable technology that gives excellent results. I recommend to everyone.

The rim of the speaker basket was smeared (out of sin) with lithol. Then I applied silicone sealant (it gives excellent results) along the edge of the hole in the case. To prevent the head from sticking, you need to lay strips of thin cellophane along the silicone track (pieces of a bag called “T-shirts” are quite suitable). Next, you need to attach the speaker, orienting it the way it will stand in the future, and screw it in with all the screws. After the sealant has hardened, the speaker and cellophane should be easily detached, and a silicone gasket that ideally fits the specific head should remain on the body.

conclusions

In my opinion, the subwoofer turned out well. Not particularly heavy, but tough and durable. In the end, it turned out to be about 33 liters - not much less than calculated, but this is not so scary: adding sound-absorbing material inside allows you to correct this discrepancy... It fits in the trunk like a glove, does not rattle, the walls do not “breathe” even at near-maximum volume. In general, I'm pleased. At that moment, I do not have the opportunity to measure the frequency response, so I tuned it by ear - adding or removing acoustic ballast or sound absorber.

On April 15, 2000, the opportunity arose to test the subwoofer in action at the first competition of the SPL club. It came as a complete surprise to me, but the subwoofer in the “SOLO” category demonstrated a sound pressure of 132.5 dB - the best result among all participants. For one “twelve” this is very serious.

Source: Magazine "AvtoZvuk" 2002 #5, Dmitry Tsypchenko.

• Author: admin
• Print

Rate this article: Share with friends!
Related posts:

Making body kits with your own hands (using the example of eyelashes for headlights)

Installing a subwoofer on a VAZ 2109 with your own hands.

Production of podiums for front doors for VAZ 2113-2115

Interior decoration

Upon completion of assembly, you should take care of the protective coating of the body and internal parts of the product:

• External surfaces are coated with varnish impregnation;
• The internal parts of the structure must be glued with anti-vibration material;
• The joints and places where the planes are attached are re-glued or impregnated with some durable compound with special attention.

Box assembly professionals use more anti-vibration material, covering not only the internal, but also the external parts of the product. Thus, the low frequencies begin to sound much better.

MFR Engineering Design Tool

Subwoofer Design Toolbox is an easy to use yet powerful subwoofer design software. The user-friendly tab interface allows you to select the design of the box, port, enclosure and subwoofer selection tools. It works on Windows XP, Vista, Windows 7, 8, 8.1 and 10. The design tool allows you to create sealed, ported and strip boxes. It also includes "free-to-air" modeling for car audio applications.

It will not be difficult for the user to determine which subwoofer box is needed; they just need to enter the driver parameters, housing type and unit volume. For ported designs, the program will recommend the port frequency, or you can select your own port. Passing bandwidth is easier than ever before. After selecting the volume, the frequency of the ports is automatically optimized. The Design Toolbox subwoofer fully supports metric measurements.

The autoresponder function allows you to see the effect of the submaster's work in a wide range of sizes. For home subwoofers or convertibles, you can select a 2D setting. Otherwise, you can choose the setting that most accurately describes the vehicle. With the Subwoofer Design Toolbox, it's easy to compare the frequency response of different block designs on one graph. Using the cursor, you can accurately determine frequency points and their sizes.

Decor

The appearance of the newly assembled box should be similar to the overall interior of the car. Products made of plastic or glass require virtually no modification, since such materials combine well with the style of modern vehicles. Wooden structures are much more noticeable and eye-catching elements that must be brought into a decent appearance. This can be done using ordinary paint, fabric or anti-vibration material.

By covering the outer planes of the box with such compounds, you will get a device that looks good in its place.

AJHorn 6 Case Modeling

Thanks to its modular design, AJHorn offers modeling of different types of subwoofer boxes with the same calculation algorithm. This is interesting because the theory behind horn design is not limited to just one type of enclosure. An ideal solution for acoustic environments where edge cases such as transmission line, bass reflex, passbands and closed enclosure types are included.

The corresponding AJHorn projects (hrn files) can be found in the AJHorn installation directory, they provide the following constructs:

1. Front speaker. Frontloaded Horn is a situation in which the front of the driver produces acoustic force along with the horn. The rear of the driver emits sound in a closed or ventilated chamber (RC) with a VRC volume. The length of a closed rear chamber with sufficient damping does not affect the simulation result.
2. Rear horn. The difference between the boot and the front horn is the discarded rear camera. The driver emits sound directly above the cone. Thanks to this modeling capability, older designs (classic rear horns) can be improved if there is still an unused area. This feature allows you to simulate and optimize a device with AJHorn.

DIY repair

Basic repairs to the audio system installed in a vehicle can be carried out even by a person who does not have any impressive knowledge in the relevant field. There are several types of breakdowns that can cause a subwoofer to suddenly stop working:

• Mechanical damage to the structure;
• Head burnout due to inadmissible frequency;
• Diffuser failure;
• Column failure.

Repairing a loudspeaker is a simple task that does not require any special skills or abilities. At the initial stage of repair work, you should disconnect the coil, taking special care. After dismantling the coil, unwind the turns of the old wire, counting their number. Then you should measure the diameter of the wire using a micrometer or caliper. You can rewind the coil using ordinary strips of thin paper - insert them in a circle at the places where the device is mounted. This will ensure an even gap.

Connection types

Installation diagram for an active subwoofer
Connecting a subwoofer depends mainly on the type of car. There are 3 main types of machines:

• Sedan;
• Hatchback;
• Cabriolet.

However, to install a subwoofer in each type of car, a special approach is required.

Sedan

Active subwoofer installation diagram

Installing a subwoofer in such a car is difficult, so you will have to tinker with it. It is best to install low-frequency heads in such a car. So:

• It is better to install them directly on the rear shelf.

Note: Any subwoofer can be installed here. Its design may also be different.

• Subwoofers are also mounted in armrests. You need to pay attention to the holes. They should be quite large, otherwise there is a possibility that the diffuser will remain closed, and because of this the sound will be somewhat distorted.

Hatchback

Speaker in a hatchback

The easiest way to install a subwoofer is in cars of this type. When choosing a subwoofer for this model of car, you must take into account that the most accurate sound is provided by devices with 10-inch heads.

Cabriolet

Where can you install speakers in a convertible?

But installing a subwoofer in a car with a convertible body type is the most difficult. This is primarily due to the fact that there is very little space here, so there is absolutely not enough space for woofers.

Subwoofer enclosure assembly

To properly make a box for a subwoofer, before screwing in a self-tapping screw, drill a hole for it with a thin drill, this will increase the strength of the fastening and protect the plywood from delamination. Distribute the number of screws evenly along the length of the side and make sure that they do not meet at the corners.

Almost always a template for cutting out the mounting hole comes with the sub; it can be part of the box or be a separate attachment. Cut out the template, transfer it to the front side of the box and cut it out with a jigsaw or router.

Template for mounting hole (cut from box)

If you don’t have such a template, you’ll have to arm yourself with a compass. When marking and cutting out the hole for the speaker, be very careful! The basket shelf is almost always narrow. If you cut less than required, the subwoofer basket will not fit into the hole; if you cut a little more or not exactly, the sub will not fit tightly or the mounting screws will hang in the air.