Wow what a coincidence! I got excited because I thought someone had posted my project which is also called Ddsp! Mine stands for D Digital Signal Processing since it is written in D.
Sorry about that :), definitely an interesting coincidence. Funny enough we actually were thinking of naming dDSP (as in derivative of DSP) but had already submitted the ICLR paper so just stuck with all caps (also because python is all lowercase).
Just going to shamelessly post it here. https://github.com/ctrecordings/ddsp
It's always great to see more DSP projects though!