How Audio Speakers Use High-Pass Filters
A high-pass filter is used in an audio system to allow high frequencies to get through while filtering or cutting low frequencies. A high-pass filter is used with small speakers to remove bass, for example. In many cases, these filters are built into the speaker, but in some more elaborate do-it-yourself speaker setups, a high-pass filter unit can be wired to the system.
How High-Pass Filters Work With Microphones
Some brands of microphones include a selectable filter. These devices, usually intended for higher-end recording, automatically block sounds below a specific hertz rating. These settings are useful when recording in places like office buildings or warehouses where the HVAC system maintains a low rumble. These filters capture the signal while eliminating the nose.
How to Use High-Pass Filters in Audio Editing
In tools like Audacity, a high-pass filter that’s applied to a waveform simulates a hardware filter. It attenuates sound below a given threshold. Specify a frequency in hertz and the roll-off in decibels per octave. Audacity then attenuates the relative volume (the dB) of the signal with increasing intensity the further below the threshold frequency the signal lies. Many audio-editing environments include similar functionality.
How High-Pass Filters Work
A high-pass filter (like its cousin, the low-pass filter) uses some technique to eliminate or reduce input below a specific threshold. There’s no specific way that it works. Some filters offer a hard cap, effectively silencing noise below the threshold, while others taper off the signal below a certain point.
