Many movie fans want to have a personal home.cinema, but not everyone can afford such a whim. Everyone comes out of this situation in his own way: someone will acquire simple Chinese speakers, someone will adapt Soviet-made acoustics to bass, and the most advanced, owning knowledge of radio engineering, will construct a low-frequency subwoofer channel independently. Especially since it's pretty easy.
General information
Consider what constitutes an ordinarysubwoofer. In fact, it is a simple active low-pass filter, to the input of which signals from a linear output (right and left channels), an amplifier and a woofer are fed. In this article we will look at the most complex element of the device - a scheme that allows you to independently assemble the low pass filter for a subwoofer. Such devices reproduce frequencies not exceeding 40 Hertz. They are used in conjunction with small satellite speakers. Subwoofers are active and passive. The latter are a low-frequency head connected to a common amplifier. Such devices are ineffective and unpopular. Quite another thing - the first option. In such devices, an electronic split active bass filter for the subwoofer and a separate power amplifier separate the bass from the signal that is fed to the main loudspeakers directly at the point of the input path where filtering this signal will bring the least level of non-linear distortion compared to filtering the output power amplifier. Adding a separate amplifier to the subwoofer channel will significantly increase the dynamic range, as well as relieve the amplifier of medium and high frequencies from the additional load.
Filter for subwoofer: schemes
The reader is invited to consider threevariants of such a device. In the first scheme, the simplest filter for the subwoofer, designed as an adder on a single transistor, is proposed. Serious sound quality with such a device cannot be achieved, but, due to its simplicity, it is perfect for novice radio amateurs. But the filter for the subwoofer, presented in the following two versions, with great success has established itself as a device with excellent characteristics. Such devices are installed directly after the linear output of the source and the input of the power amplifier. Subwoofer Filter characterized by low noise, low power consumption, as well as a wide range of supply voltage.
Conclusion
Summing up, let's say that adding a subwooferactive type significantly reduces the lower limit of the reproduced frequencies, increases the purity of the sound at medium frequencies and provides a fairly high level of volume without distortion. Eliminating low frequencies from the spectrum of the main reproducing signal arriving at the satellites allows them to sound cleaner and louder. This is due to the fact that the cone of the low-frequency head does not oscillate with a large amplitude, trying to reproduce the bass and thereby introducing distortion in the signal.
