Channel (audio)

An audio signal is a representation of sound, typically as an electrical voltage. Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz (the limits of human hearing). Audio signals may be synthesized directly, or may originate at a transducer such as a microphone, musical instrument pickup, phonograph cartridge, or tape head. Loudspeakers or headphones convert an electrical audio signal into sound. Digital representations of audio signals exist in a variety of formats.

An audio channel or audio track is an audio signal communications channel in a storage device, used in operations such as multi-track recording and sound reinforcement.

Signal flow is the path an audio signal will take from source (microphone) to the speaker or recording device. It is most frequently in a recording studio setting, where the signal flow is often very long and convoluted as the electric signal may pass through many sections of a large analog console, external audio equipment, and even different rooms.

Audio signals may be characterized by parameters such as their bandwidth, power level in decibels (dB), and voltage level. The relation between power and voltage is determined by the impedance of the signal path, which may be single-ended or balanced.

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