Bit Depth
How many bits represent each sample, and therefore the theoretical dynamic range
Related
Bit depth is the number of binary bits used for each sample. More bits give finer amplitude steps, a lower quantization noise floor and a wider theoretical dynamic range; the rule of thumb is 6 dB more range for each added bit.
CD audio at 16 bits has a theoretical dynamic range of 96 dB. At 24 bits it is 144 dB, beyond the noise floor of most recording rooms, which leaves headroom for recording levels and later processing. Bit depth does not set the frequency ceiling; that is the job of sample rate.
The usual mistake is to treat bit depth as a quality grade and assume 24 bits always sounds better than 16. For playback, 16 bits already covers the dynamic range of normal listening. The main value of 24 bits is during recording and mixing, and in reducing accumulated error across repeated processing.
Related → Sample Rate
Sources
- 位深、量化噪声与每比特 6 dB 动态范围的通行表述，参 Modern Recording Techniques（Huber & Runstein）与 The New Grove Dictionary of Music and Musicians, "Sound recording"；本文为原创表述
Used for fact-checking only; all prose is original.