[erdewit]

Other lossy compression methods generally happen in the frequency domain and, depending on the type of music, can introduce audible distortions.

This preprocessor on the other hand throws away some of least significant bits to save data. This increases the quantization noise but has no other sort of artifacts. The quantization noise can be dithered to fall in the higher frequencies (noise shaping) and is generally not perceptible.

[Dylan16807]

Doesn't 16 bit audio already require dithering to capture the full audible dynamic range? That makes me worry somewhat about cutting more bits and layering dithers on dithers.

[TonyTrapp]

While it's good practice, a 16-bit recording is usually not exactly ruined by not dithering it. 96dB dynamic range is a lot.

[astrange]

You always want dithering no matter the bit depth, but 16-bit is actually quite a lot - there's literally no point in better than CD-quality audio. (Except of course that real life is in surround not stereo.)

But yes, if you're doing it repeatedly you'd want an un-dithering filter. Noise reduction tends to do this by accident but it helps if you know what the dither shape was.