A sort of odd phrase that has come into use to describe how many bits a digital recording or digital device uses. In digital audio the sample rate (or sample frequency) will determine the upper limit of audio bandwidth that can be digitized. The number of bits in each sample determines the theoretical maximum dynamic range of the audio data regardless of sample rate. Each additional bit adds 6 dB to the dynamic range of the audio. Bit depth is just a phrase occasionally used to specify how many bits are being or have been collected in the data. A 16-bit recorder, for example, would produce digital files with a bit depth of 16. The “depth” concept arose out of illustrations describing the effect of more bits on an audio recording. If dynamic range is looked at as a vertical line, the upper limit of which is always fixed at 0dBFS, more bits produce a line that goes deeper into the noise floor and lower ranges of audio to be captured. More bits help capture quieter data more accurately.