Digital Audio Fundamentals

Information about digital audio production, processing and editing, as well as resources available at the Library.

Terms used in the guide

Amplitude: The magnitude or strength of a sound wave, typically measured from its peak to its baseline.

Audio data compression: The process of reducing the size of digital audio files to save storage space or bandwidth while preserving sound quality (not to be confused with analogue-to-digital conversion, which is typically abbreviated as ADC).

Attack: The initial phase of a sound envelope that represents the time it takes for a sound to reach its maximum intensity.

Bit depth: The number of bits used to represent the amplitude of a digital audio signal, determining the resolution and dynamic range of the audio.

Compression: The reduction of the file size of audio data through various techniques while attempting to maintain acceptable sound quality.

Decay: The gradual decrease in the amplitude of a sound signal after the initial attack phase.

Delay/echo: A time-based audio effect that produces a delayed repetition of a sound, creating an echo or reverberation effect.

Digital audio workstations (DAWs): Software applications used for recording, editing, and producing digital audio and music.

Equalisation: The adjustment of audio frequencies to enhance or attenuate specific parts of the sound spectrum.

Gain: The increase in the amplitude or volume of an audio signal.

Generation loss: The degradation of audio quality that occurs when making successive copies or conversions of a digital audio file.

kiloHertz (kHz): A unit of frequency equal to one thousand Hertz, commonly used to specify the sample rate in digital audio.

Knee: In audio compression, the point at which a compressor starts to affect the signal, transitioning from no compression to full compression.

Lossy/lossless formats: Two types of audio compression formats—lossy formats sacrifice some audio quality to achieve higher compression, while lossless formats retain all original audio quality.

Phantom power: A method of delivering electrical power to condenser microphones and other devices through audio cables.

Polar pattern: The directional sensitivity of a microphone, indicating how it captures sound from different angles.

Quantisation: The process of approximating the amplitude of an analogue audio signal to a discrete value in digital audio, often determined by bit depth.

Ratio: In audio compression, the proportion of input level to output level, determining the amount of compression applied to the signal.

Release: The final phase of a sound envelope, representing the time it takes for a sound to fade out after the sustain phase.

Resolution: The level of detail or clarity in digital audio, often determined by factors such as bit depth and sample rate.

Reverb: The reflection of sound waves in an enclosed space, creating a sense of space or ambiance in audio recordings.

Sample rate: The number of audio samples captured per second, determining the frequency range and fidelity of digital audio.

Sustain: The portion of a sound envelope that represents the level of intensity maintained after the attack phase.

Threshold: The level at which audio compression or gating is triggered, typically measured in dB.