Sounds like it's almost certainly the receiver. The electricity seems unlikely to me, and if you're getting it through the headphones and the speakers, it's definitely not the speakers.
that seems reasonable -- i'm worried though, what are the chances that the receiver damaged the speakers? NB i don't play my music especially loud; surely there are moments when i crank it but i've never even got that volume knob to the 12 o'clock position before.
and just now i tried my headphones through my mixer in another room and,
i still noticed the crackle....
