HPF — High-Pass Filter
Definition
A high-pass filter (HPF), also called a low-cut filter, passes frequencies above its cutoff and attenuates those below it. On a mixing console, the channel HPF removes stage rumble, handling noise, plosives and vibration transmitted through microphone stands. Common starting points are about 80 to 120 Hz for vocals and 100 to 150 Hz for many instruments, with the filter off or set very low for kick drum and bass. The slope is expressed in dB per octave and is commonly 12 or 24 dB/octave.
In the field
Many engineers engage a high-pass filter around 80 to 100 Hz on most channels that do not carry low-frequency content. Removing the energy below 100 Hz that those sources do not need clears the mix, recovers headroom and reduces low-frequency feedback and stage rumble.
Related lessons
Sources
- High-pass filter (Wikipedia) : définition, pente en dB par octave · en.wikipedia.org
- Shure, « How to Control Feedback in a Sound System » : égalisation et réduction du larsen · shure.com
- Ballou, Handbook for Sound Engineers : filtres de voie des consoles