Nick Sevilla wrote: ↑
Mon May 25, 2020 4:53 am
Dithering is from the days of "not loud masters" going from an analog transfer to a digital one (think 1980s to 2000s), and with shit sounding converters, at least as compared to what we enjoy today. And even back then it was only used when necessary, not all the time.
I'm sorry, but no. To avoid truncation distortion, dithering is required any time you reduce the bit depth, e.g. from 24 to 16 bits. It has nothing to do with how loud a mix or master is, unless the mix was peaking at like -60, which never happens.
If you're exporting a mix at 24 bit, or just rendering a file as 24 bit, technically you should dither this, as your DAW is working at 64 or 32 bit floating point internally. However at the 24 bit level, the truncation distortion would be at -144 dbfs (properly dithered, the noise floor would be -132dbfs), which is impossibly quiet and way below the noise floor of anyone's converters, so it's arguable whether it makes any real-world difference at 24 bits. Still, correct is correct, and it's not like it's difficult to do.
You can avoid having to think about this at all by simply rendering stuff as 32 bit float, it's what I've been doing forever.
Otherwise, when mastering, dithering to 16-bit should be the last thing done, after SRC and limiting. Regular old TPDF works just fine, there is absolutely no reason not to do this, dither is a good thing.