On Wed, 21 Jul 2010 09:46:59 +1000, Phil Allison wrote:

"Reverend Fuzzy"

If there is a cross-over board in the case, you may have an electrolytic
capacitor going bad.
When they over heat, they'll make those sort of noises.

** That is utterly bizarre crap.

Can't say I've heard an x-over cap his but I've seen them over heat as
evidenced by broken and distored shrink wrap covering .