TPDF Dither Redux

TL;DW: I’ve revisited TPDFDither, to add a 16/24 bit switch and DeRez.


This continues my Redux series of dither plugins. Now, TPDF! As I say in the video, this is not only 16/24 bit TPDF with a DeRez control (and a clamp for how loud it gets so it doesn’t blow up your ears at super low bit depths), it’s also the Airwindows TPDF algorithm. Which is to say it’s not exactly like everyone else’s TPDF algorithm, even though it adds exactly two noise sources each one bit in loudness.

That’s because when I made it, I added one and then subtracted the other and thought that gave me zero. But of course, it doesn’t… it gives me TPDF (triangular probability density function, or ‘the correct kind of dither when done by-the-book’ which decorrelates two moments of quantization noise blah blah blah technical :) )

But it also gives exactly half a bit, on average, of DC offset. This is enough to make measurements weird. It’s not enough to do any harm to anything (less than a least significant bit: it’s literally in the noise floor). But it is enough to have the noise floor sit across THREE bit values instead of only two. And that is enough to make it sound nice. (it’s possible there are other values, like 0.382… that would sound better still, but I’ve not done that experiment yet, and it’d be more complicated to implement… guess I know what I’ll be doing NEXT week)

This work is supported by Patreon, and thanks to that I’m able to buy a pump to empty my busted washing machine. After first buying a microphone, instead of a non-busted washing machine. Because of course I did :D