Anything class D that I’ve ever taken a flyer on.
Any digital processor or digital crossover.
I’ve taken each of them apart (multiples of each) and rebuilt them as best as possible, still --no joy.
PTSD. I now have nightmares about self powered speakers with class D amps and digital crossovers. Coming after me with axes and the like. Every time we go to a concert, these days, it's all we'll ever get. Live sound (for the most part) has gone totally to hell.