Simple Explanation

A tool that removes just one specific frequency from the sound, like a scalpel for audio.

Concise Technical Definition

A highly selective, cut-only filter designed to sharply attenuate a narrow band of frequencies while leaving others unaffected.

Layman-Friendly Analogy

Like muting just one string on a guitar without touching the rest—it silences only that pitch.

Industry Usage Summary

Used in live sound, recording, and acoustic correction to eliminate problem frequencies such as feedback, hum, or ringing without affecting the rest of the signal.

Engineering Shortcut

Narrowband attenuation filter—used to surgically remove unwanted tones.

Full Technical Explanation

A notch filter is a cut-only equalizer designed to attenuate a very narrow band of frequencies, leaving adjacent frequencies mostly unaffected. Also known as a band-stop or band-reject filter (with a narrow bandwidth), it is commonly used to eliminate specific unwanted tones—such as 60 Hz electrical hum, feedback frequencies, or ringing modes in live sound or studio settings. The filter is defined by its center frequency, bandwidth (Q factor), and depth of attenuation, and may be implemented using analog circuits or digital signal processing (DSP). Notch filters are valuable in applications where surgical correction is needed without compromising the tonal integrity of the overall signal.