Glossary of Audio, Recording
and Music Terms "Q"
Q – (Also called “Q Factor”) – Stands for “Quality Factor,” defining the bandwidth of frequencies that will be affected by an equalizer. The lower the Q, the broader the bandwidth curve of frequencies that will be boosted or cut.
Quadraphonic – A now rarely-used system of four-channel sound where the channels are designated as left front, left back, right front, right back, intended to deliver sound from all four corners of a room. Quadraphonic sound was a precursor to the surround-sound systems of today.
Quantization – 1) In digital music, the process of adjusting the rhythmic performance of music by moving the notes to precise locations on the time line, effectively “rounding” the note occurrences to the nearest defined increment. 2) In analog-to-digital conversion, the use of the same mathematical quantization principles to convert an analog signal into a smaller set of steps (a digital quantity).
Quantization Distortion/Quantization Error – The effective “error in translation” between an analog signal and its sampled counterpart due to the rounding of a large number of analog values to the nearest digital quantity. This often results in additional random frequencies in the sound, often heard as noise.
Quantization Noise – The modulation noise in a signal resulting from quantization error.