Specs & measurements

Bit depth

Also called word length, 16-bit, 24-bit

Bit depth is how many bits describe each audio sample: 16 bits for a CD, 24 bits for most hi-res files. More bits lower the noise floor of the digital format, giving a wider dynamic range, rather than adding detail to the music.

Rounding each sample to a fixed set of levels leaves an error that acts as noise, and each extra bit halves it, lowering the noise floor by about 6 dB. Sixteen bits give about 96 dB of dynamic range; 24 bits give a theoretical 144 dB.

Each extra bit adds about 6 dB of Dynamic range. Sixteen bits give around 96 dB, and with dither and noise shaping the usable range is wider still, more than any home listening needs; 24 bits give a theoretical 144 dB that no DAC or room achieves. The benefit of 24 bits is headroom during recording and processing, where rounding errors accumulate.

Dithering, which adds a tiny amount of noise when reducing bit depth, makes 16-bit playback effectively transparent. That is why CD quality and 24-bit hi-res of the same master are hard to tell apart in tests.

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