What is an audio equalizer?

An audio equalizer is a device used to adjust the balance of frequencies in an audio signal. They offer fine control over the various frequencies reproduced in recorded music, giving listeners more control over the audio quality to suit their own personal tastes.

By attenuating or boosting various frequency bands, equalizers can be used to:

- Correct unwanted resonances or deficiencies in the listening environment or audio equipment.

- Compensate for natural auditory characteristics, such as the Fletcher-Munson equal-loudness contours which describe how humans perceive sound at different frequencies and sound pressure levels.

- Achieve specific effects, such as adding warmth or clarity to a sound, simulating different listening environments, or matching frequency response to particular types of music or voices.

Equalizers are widely used in audio engineering, music production, sound reinforcement, broadcast engineering, and home audio applications. They're available as standalone devices, as software plug-ins, and even as built-in features in audio players, sound cards, and receivers.