Audio signal

An audio signal is an electrical or digital representation of sound that varies over time, encoding changes in acoustic pressure or related sound information.

Sound pressure: The deviation of air pressure from its ambient value as a sound wave passes. A microphone converts these acoustic pressure variations into an electrical signal.
Waveform: A representation of how a quantity varies over time or space. An audio signal's waveform displays its changing value over time.
Audio recording: The capture and storage of sound as an audio signal. Recording preserves an audio signal for later editing, playback, or distribution.
Sound: Mechanical vibration that propagates through an elastic medium as pressure or displacement waves. Sound is a physical phenomenon; an audio signal is its electrical or digital representation.
Microphone: A transducer that converts sound into an electrical signal. Its output is an analog audio signal that follows incoming sound pressure.
Amplitude: The magnitude of a signal's displacement from its reference level. Signal amplitude relates to sound pressure level and perceived loudness.
Digital audio workstation: Software for recording, editing, mixing, and producing digital audio. A workstation manipulates audio signals as tracks, samples, and effects.
MIDI: A protocol for transmitting musical performance instructions and control messages, rather than recorded sound. MIDI describes notes and events but is not itself an audio waveform.
Analog signal: A continuous signal whose values vary smoothly over time. An analog audio signal represents sound through continuous voltage or current changes.
Frequency: The number of cycles of a repeating event per unit time. Audio frequency is closely related to the perceived pitch of a periodic sound.

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