Q & A What is Dither?
The Question: I have heard that dithering is essential, when changing the sample rate of an audio file. Why?
The Short Answer: Dither is low-level (as in quiet) noise that gets added to a signal to aid in the conversion of “bit-depths.” Basically you only NEED dither when you’re going from one bit-depth to another. For example you’ll want to include dither when going from 24-bit to 16-bit.
One important note: You do NOT need to add dither when only converting sample rates – like 48 kHz to 44.1kHz sample rate.
One important tip: You’ll get better results if you do sample rate conversions of mixes second-to-last and then bit-depth conversions last.
The Longer Answer: Dithering is a procress by which you can increases the theoretical potential dynamic range of an audio system. A 16-bit file has potentially about 96dB of potential dynamic range (bit depth * 6). Through more math and physics than I want to get into (because it still confuses me at times) dithering can increase that potential dynamic range significantly – by making resolution clearer in the quieter range of sounds. It basically helps the reduce the distortion inherent in bit-depth reduction – think of the sounds you get when you put a bit-crusher on a track.
(I’ll try to add more to this later, but it’s going to take some delving into my old school notes and a bit of book reading.)
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