Simple Explanation

A tool that blocks some parts of a signal and lets others through—like removing bass, treble, or noise.

Concise Technical Definition

A device or circuit that attenuates certain frequencies while allowing others to pass, based on defined cutoff points.

Layman-Friendly Analogy

Like sunglasses for your ears—it blocks out too much brightness (highs) or rumble (lows), depending on what you want to hear.

Industry Usage Summary

Filters are used in audio systems, recording, mixing, electronics, and communication systems to shape frequency content. Types include low-pass, high-pass, band-pass, and notch filters.

Engineering Shortcut

Frequency-selective circuit: blocks or passes defined bands (LPF, HPF, BPF, notch).

Full Technical Explanation

A filter is an electrical, electronic, acoustic, or optical system that selectively attenuates or passes signals based on frequency. In audio, filters are used to control tonal balance, reduce unwanted noise, and shape signals in mixing or playback systems. Filters can be active (amplified) or passive (resistive/capacitive), analog or digital. Common types include low-pass (blocks highs), high-pass (blocks lows), band-pass (allows a range), and notch (cuts a narrow frequency). Filters are essential in loudspeaker crossovers, EQs, DSPs, and many signal processing chains.