Do you want a subwoofer in your car, but don't like having a bulky square box in the trunk? Why not create a DIY car subwoofer from fiberglass that will fit into your car's interior and look factory? Most cars have unused space in the trunk that is ideal for installing a subwoofer.
Working with fiberglass is not very difficult, and the material is excellent for creating a body. I will show diagrams and drawings of how you can make a subwoofer enclosure that will look like it came with the car.
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- equivalent volume;
- acoustic resonance frequency in open space conditions;
- maximum noise power;
- diffuser diameter;
- speaker quality factor;
- electrical quality factor;
- mechanical quality factor;
- impedance of your speaker.
If you are using standard speakers, then some parameters are already set and do not need to be changed. You can search for the necessary information through the manufacturer’s website, find data on the Internet and see what is indicated on the packaging. If you ordered some strange speaker from China, you may not be able to find information on it.
In this case, the key parameter is considered to be the quality factor of the speaker, which is designated as Qts. This parameter describes the performance of the speaker at resonant frequencies. When you enter all the specified parameters, the program will give you one type of box for the sub as an answer. There are 3 options in total, each of which has its own strengths and weaknesses.
The boxes are:
- standard closed;
- bandpasses;
- bass reflexes.
The first option is the simplest in terms of manufacturing and creating a project. But the efficiency indicators are low. It is also important to comply with strict requirements for the tightness of the box.
The other two are better in terms of sound, but making them yourself is extremely problematic.
Final design stage
Working through the program, you will need to create a new project for your future sub.
The sequence of operations is approximately as follows:
- First, a new speaker is created, after which its parameters will need to be loaded into the database;
- Next, a project is created based on the box that you chose or the program recommended to you;
- To complete this step, you will need to follow the previously described procedures again;
- Design includes making changes to the box, adjusting the frequency and other parameters.
By changing the parameters, the graph with frequencies will change in parallel. You should try to make sure that at 25 to 35 Hz the graph crosses the -3 dB line, then follows the line to 0 dB, and then moves downward at 150 to 200 Hz.
Simple subwoofer for a car
The easiest way is to make a subwoofer in a car without an amplifier with your own hands. This does not require knowledge of radio engineering, so independent assembly and adjustment of the amplifier is excluded. To make a passive low-frequency speaker, in addition to the loudspeaker, you will need the following parts:
- Housing material
- Self-tapping screws
- Silicone sealant
- Terminal block
- Acoustic cable
- Filler for internal volume
- Carpet type material
After selecting and purchasing a speaker, you can make the housing. Most often, multilayer plywood or MDF is used as a material for the manufacture of speaker cabinets. The wall thickness must be at least 18 mm to avoid a booming resonating sound. Plywood of this thickness is difficult to find, so choosing MDF would be the best solution. The material is easy to process, and the individual elements are well connected with self-tapping screws.
The front wall must be made of two plates. To increase the rigidity of the structure, all edges must be coated with glue before screwing in the screws. The dimensions of the magnet for different types of speakers may differ, so the size of the housing is determined by the dimensions of the loudspeaker. To make the box more durable, assemble the subwoofer into the car with your own hands, it is better to use 25 X 25 mm bars. After completing the assembly of the box, all seams must be treated with silicone sealant.
Homemade subwoofers for cars can be made with an acoustic bass reflex or bandpass circuit. The housings for such acoustic speakers have a complex design and special formulas are used in the calculations. A speaker with an acoustic bass reflex is approximately twice the size of a closed box. Despite the high efficiency, the sound of low frequencies is not so clear and the bass is a little blurry.
Antiacoustics
This is a very important part when arranging a home theater and a subwoofer in particular. You need to create excellent anti-acoustics, especially if you do not live in your own house, but in an apartment building.
Neighbors may complain about the loud noise, and they have a right. Create high-quality sound isolation and watch TV shows and movies, listen to music as much as you want.
The first thing you need to stock up on to create proper sound insulation is special acoustic foam. This is a fairly popular material that musicians regularly use to decorate their home music studios.
It is characterized by high efficiency and low cost. You can find soundproofing foam on various Internet resources from third-party manufacturers, then the price will be even lower.
You can also upgrade the existing walls in your home so that they add anti-acoustics and sound insulation. There is a special ceiling shape design that cannot be installed at home, but if you spend money and order the design from professionals, you definitely won’t regret it.
Subwoofer design
The next step will be to create a project for the future subwoofer. Before assembling the case, it is recommended to perform some calculations. You can see something in the video, study the experience of making subs by other car enthusiasts.
But it’s still right to make a project specifically tailored to your speaker and car parameters. There is even a special almost professional program for such purposes. It's called Win ISD. Some parameters are entered into it, as a result of which you get a project for the optimal subwoofer.
You should know about:
How to make a housing for a subwoofer with your own hands
If you need to make a good box for a subwoofer, then it is best to focus on the most complex design. This system is called a bandpass. It comes in fourth order and sixth order. The fourth-order system is a two-chamber box, where one chamber is a closed box, and the other plays the role of a bass reflex.
A sixth-order bandpass is a design with two bass reflexes. The most difficult thing here is the calculation of the second port and the relative relationship of the settings of each bass reflex. The two chambers have different sizes and are capable of limiting the frequencies reproduced by the loudspeaker. The box for two subwoofers is the most difficult to design, but it has the maximum efficiency. To determine all sizes of such sound systems, special utilities are used. The universal WinISD program is suitable for calculating any subwoofer design. It does not have a Russian-language interface, but it is not difficult to understand. To make a drawing of a box for a subwoofer, just load the parameters of the speaker you are using into your computer.
Filters
Yes, installing filters is not a necessary procedure if you are going to use the subwoofer in a country house, where no one will hear and you will not disturb anyone. In addition, filters prevent certain sound defects caused by excessive bass or too loud sound effects.
Subwoofer filters are a fairly affordable and inexpensive accessory that almost everyone can afford. Similar items are sold in a special themed music equipment store.
If there is no such store in your city, then try to find music filters in an electrical and computer instrument store.
Filters are necessary for the proper functioning of a homemade subwoofer.
Rules for using someone else's trailer on a car
- 6-inch. Used as sources of mid-bass when combined with large subs;
- 8-inch. Well suited for those who need front bass;
- 10-inch. Suitable for speakers with an internal volume of 15-20 liters;
- 12-inch. They produce excellent sound quality, but the box will have a volume of at least 25 liters;
- 15-inch. Incredibly powerful bass, but the case takes up a minimum of 60 liters. Or even all 90.
Before assembling your flat or surround sub, be sure to think about choosing the voice coil resistance. One simple rule applies here. The lower the resistance of the amplifier, the higher the power parameter will be.
The mistake of many is choosing devices with a minimum value. If you place a subwoofer with similar resistance under a seat or anywhere else, the sound quality will suffer greatly. It is optimal to choose about 2-4 ohms. But it’s better to refuse 1-2 Ohms.
As for power, specialists and ordinary car enthusiasts do not have a consensus on this matter. But I can say one thing for sure. It is optimal when the power of the selected speaker slightly exceeds the power parameters of the amplifier used. We must not forget that almost all systems are not designed to operate for a long time and at maximum power. Gradually, in this mode, the sound quality will decrease and various distortions will appear.
Choose wisely, keeping in mind that all this equipment will have to be installed somewhere. It would be correct if the built-in subwoofer does not disturb the interior space, and also does not become an obstacle in the luggage compartment of your VAZ 2107 or any other car.
Making computer calculations
Quite an important part of installing your own subwoofer. You should not rely one hundred percent on the devices and tools that you purchased. To be completely sure and confident that your home theater is working properly, you need to make preliminary computer calculations.
Computer programs do not provide for non-trivial solutions and errors that are typical for humans. This eliminates almost all risks and the possibility of error.
JBL subwoofers often use a computer plugin called JBL SpeakerShop. A fairly high-quality program that has wide functionality and runs smoothly even on the weakest computers and laptops.
Periodically, it is worth installing such software and checking the operation and functioning of all components of speakers and subwoofers.
Car subwoofers
As already partially mentioned earlier, subwoofers are used not only for home theaters and music studios. Some drivers who lack music and drive install powerful speakers, speakers and subwoofers in their car in order to listen to music loudly.
If you are one of these people, then you should remember that you can only play loud music during daylight hours, so as not to disturb the people around you. You need to remember not only about yourself.
