High-pass and low-pass filters are common features found in home audio systems, particularly in subwoofers and AVRs. These filters are used to control the frequency response of an audio signal, allowing certain frequencies to pass through while attenuating or eliminating others. A high pass and low pass filter together form the so-called crossover, most of you will know.
A low pass filter, as the name suggests, allows low-frequency signals to pass through while attenuating high-frequency signals. This type of filter is commonly used in subwoofers to ensure that only the bass frequencies are amplified and reproduced, while high-pitched sounds are eliminated.
On the other hand, a high-pass filter allows high-frequency signals to pass through while attenuating low-frequency signals. This type of filter is commonly used in tweeters on crossover networks to ensure that only the high-frequency sounds are amplified and reproduced, while bass sounds are eliminated.
It is also the same filter that creates the bass roll-off on the speakers you set to "small" on your AVR.
Overall, high-pass and low-pass filters are essential tools for home audio enthusiasts and professionals alike. They provide a simple and effective way to tailor the sound output of a system to suit different preferences and listening environments. By understanding how these filters work, you can optimize your audio system to deliver the best sound quality possible.