One of my monitors (active) has recently been acting strange. Whenever it's turned on it emits a low pitched pulsing sine wave. There's a lot of cone travel. Quite a cool synth sound, but quite useless as a speaker.
I'm guessing it's something with the amp rather than the speaker assembly.
Sound familiar? Easy / worth fixing? (they're cheap Alesis M1 520) or should I go a-lookin' to buy a new pair?