a filter you punch holes in

Six resonant bands, drawn as six rings of lit glass round the big knob. Patch a second sound into STRIKE and it puts up a wall against the first: clockwise it cuts its own shape out of IN, so a kick punches a hole in a pad exactly its shape; counter-clockwise, IN sounds only where it does. Turn RES up and the six bands ring on their own, a six-note chord. The rings ripple when it's struck.

https://daylightnoise.com/absoluteterror/