Some knowledgable folks have asked why the AD-20 doesn't dither its
least significant bit, considering that it truncates its 20-bit data
down to 16-bits. (In some situations, truncation results in audibly
Although the AD-20 uses a true 20-bit A-to-D converter chip (AKM5351, a
slight improvement from the AKM5350 found on the ADA1000 converter), its
actual dynamic range is just around 98dB. This means that although there
may be more signal in the noise, the S/N ratio is really only giving you
about 16.5 bits of real information above the noise floor.
Ideally, once you record the AD-20's output and truncate to 16-bits,
you should dither the result in your digital audio workstation (DAW).