i think looking at audio will give some good clues since it's so analogous to light & we have decades of audiophiles spending big bucks to figure out how to tweak it.
just like our bad lights, different 'bad' sounds have different effects.
1) high pitched (semi-audible, in and out of perception range), single-frequency sounds are fatiguing or headache producing. most electronics create these. [like leds?]
2) static/white noise (evenly spread frequency range) is relaxing, focusing, [like sun, incandescent lights?]
3) low-frequency sounds 50hz etc. are used to put people in trances, different meditative states, fear. these frequencies can be layered under the 'main' sound. [pwm levels?]
4) distortion happens (at any point in the signal chain) when the signal is too hot for the device handling it & 'clips' resulting in a square wave & lots of high-pitched 1 type sounds/harmonics. (Cassette tape and tube amps saturate in a nice way when this happens, digital stuff just distorts horribly) [if you look at leds in videos they are almost always clipping/overloading the camera. I bet they do this to our retinas as well.]
5) audio dithering, higher bit rates, are concepts used to turn (on/off/digital) square waves into an approximation of nature's (rounded/analogue) sine waves. [pwm'd FRC'd LEDs require our brain to do the dithering?]
There are lots of other audio concepts that could fit in too.. aliasing, compression, phase cancellation, stereo imaging(for 3d spatialization).