A quality branded subwoofer is expensive. There are many explanations for this: these are special acoustic requirements for the case, and a high-quality speaker, and a large output stage power, and a special, very careful factory adjustment.
So, the body. At low frequencies, all the flaws of any speaker system appear. The resonant frequencies result in unwanted vibrations that are felt as rattling. In order to avoid incorrect sounding, the subwoofer enclosure is clogged with sound-absorbing fibrous fillers, but if the shape and dimensions are calculated and chosen incorrectly, then such a measure will give only a partial improvement.
The speaker is a very important design element. Its power must be at least 100 watts, and the characteristics must provide for the reproduction of infra frequencies. Now they are produced relatively small - from 6 to 15 inches in diameter.
An experienced radio amateur who has the practice of installing and configuring complex equipment can assemble an amplifier for a subwoofer with his own hands. This is not an easy task, despitethat modern semiconductor parts have a high degree of integration. It is required not only to be able to read circuits and understand the principle of operation of a low-frequency amplifier, but also to master the technique of etching boards and other useful skills, including such a simple matter as high-quality soldering.
Having gathered to make an amplifier for a subwoofer with your own hands, you immediately need to decide on the purpose of the device. If it is designed to work in a car, then the requirements for it will be the same, and if it is for a home theater, then others.
In the first case, the supply voltage is limited by the operating value of the on-board power supply, usually 12 volts with a minus on the case. The task is simplified by the fact that a powerful power transformer, amplifier and stabilizer is not required. But you will have to assemble the circuit yourself. The TDA7293 received good reviews as it can withstand high output current and provide enough power (up to 100 watts) to pump bass.
If a homemade subwoofer amplifier is designed for home cinema, then the requirements are different. You can, in fact, follow the same path and assemble it in a similar way, but you will need a sufficiently powerful transformer with a power supply, and all this must be placed inside the case, where a rather voluminous loudspeaker and phase inverter are already installed. At the same time, one should not forget about heat transfer, radiators will also take their place.
There is another way to solve the problem - notassemble an amplifier for a subwoofer with your own hands, and use a ready-made circuit, for example, from Soviet-made Amfiton or Brig-001 amplifiers. You can buy them at a very affordable price, especially if one of the channels does not work. A convenient modular system, a ready-made power supply and adjustments create all the conditions for using this high-quality equipment, and you don’t have to puzzle over how to make an amplifier for a subwoofer.
LC filters that limit the frequency range of mid and high frequencies should be placed both at the input and at the output of the device, directly in front of the speaker. When assembling an amplifier for a subwoofer with your own hands or using a ready-made circuit, you should take care of both noise limitation and the durable and reliable operation of this overload-sensitive electronic device.
And I also want to say that you should not show the results of your work to your neighbors too intrusively, they will not appreciate it.
