Dynamic Range
Definition
The dynamic range of a system is the ratio, in dB, between the highest level it can handle without clipping and its noise floor. In linear PCM, each bit adds about 6 dB, so the theoretical figure is about 96 dB at 16 bits (CD audio) and about 144 dB at 24 bits. Real equipment working at 24 bits is limited by its analogue circuits and converters, and the measured dynamic range of the best converters reaches about 120 dB. The term also describes the difference between the quietest and loudest passages of a programme.
In the field
When an engineer says a mix lacks dynamics, the level difference between its quiet and loud passages has been reduced, usually by compression and limiting, so that most elements arrive at a similar level. Keeping the dynamic range of the programme preserves the contrast between quiet passages and loud transients such as the kick drum.
Related lessons
Sources
- Ballou, p. 842, 6,02 dB par bit : 96 dB en 16 bits
- Audio bit depth (Wikipedia) : plage dynamique théorique de 96 dB en 16 bits et 144 dB en 24 bits ; convertisseurs réels limités vers 123 dB, soit environ 21 bits effectifs · en.wikipedia.org
- Dynamic range (Wikipedia), définition : rapport entre niveau maximal et bruit de fond · en.wikipedia.org
- Sound On Sound, « Recording In 20-bit & 24-bit PC Audio » : meilleurs convertisseurs vers 120 dB de plage dynamique · soundonsound.com