Ask HN: Help finding good embedded DSP design resources?

I'm working on an LED art project that combines a few realtime signals to inform the visuals, audio and some other inputs. I'm running things on an ESP32 right now and doing an FFT and some other sort of seat-of-the-pants DSP stuff on one core while the other handles bluetooth, LED control, etc. I've got some time to mess around and I'd like to get a broad strokes overview of the embedded DSP field to inform myself on where to explore next. I've got a fair bit of hands on experience but little formal training.

Ultimately the goal is to *make good art* so I'm not really looking for anything specific. In my head I'll get some good papers/textbooks/libraries/articles recommended to me and then I'll spend a few weeks to write toy implementations of whatever seems interesting in C to get a feel for the space.

I'm particularly looking for the nitty-gritty type stuff, cool hacks that save cycles and improve latency, my goal here is visceral reactivity and I'd like to get some more tools in my toolkit that allow me to interpret and combine signals in realtime in interesting ways. Even info on cool math hacks like Carmack's fast inverse square root would be appreciated.

P.S. Also of interest is material on debugging and modelling realtime code.