Audio signal

See also: Audio channel

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.

Signal flow

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.

Parameters

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.

Digital equivalent

As much of the older analog audio equipment has been emulated in digital form, usually through the development of audio plug-ins for digital audio workstation (DAW) software, the path of digital information through the DAW (i.e. from an audio track through a plug-in and out a hardware output) is also called an audio signal or signal flow.

A digital audio signal being sent through wire can use several formats including optical (ADAT, TDIF), coaxial (S/PDIF), XLR (AES/EBU), and Ethernet, especially for large digital mixing consoles.

See also

• Analog audio
• Analog recording
• Audio signal processing
• Balanced audio
• Communications
• Digital recording
• Professional audio