For a while, I have bee bothered by a crackling sound form one channel about a minute or so after first switching on my stereo. It did not seem to matter what source component I was using. After a few crackles, it goes away for the rest of the listening session. It has been driving me crazy. I suspected the amp, the pre-amp, the interconnects, etc, Yesterday, the beast started crackling just after switch on, except that I also lost sound from the offending channel. On closer examination, I noticed that the speaker sounded like a low quality transistor radio. The mid and high frequecy drivers were playing, but not the woofer. I cranked up the volume, the speaker briefly cracled once more, and the sound came back and was OK for the rest of the evening.

What gives? Is it the woofer, or could it be a fault with the crossover?

All suggestions gratefully recieved.