Simple Explanation

The point where a filter starts reducing the strength of a signal.

Concise Technical Definition

The frequency at which the signal drops by 3 dB (half power) from its maximum level; also known as the -3 dB point or corner frequency.

Layman-Friendly Analogy

Like a water tap where the flow starts to slow down—below or above this point, the flow (sound or signal) fades out.

Industry Usage Summary

Used in audio filters, crossover design, and equalization to define the frequency limits for signal processing. Engineers reference cutoff frequencies to determine where to begin attenuation in low-pass, high-pass, or band-pass filter applications.

Engineering Shortcut

Cutoff Frequency = -3 dB point = half power point.

Full Technical Explanation

The cutoff frequency marks the point at which a filter or system begins to significantly attenuate (reduce) the amplitude of a signal. Defined as the frequency where the output falls to 70.7% of its maximum (a 3 dB drop), it is essential in filter design to separate desired frequency content from unwanted. It's used in high-pass, low-pass, and band-pass filters.