I will post an update here when I get my subwoofer checked out by the audio gurus my son bought it from - wanted to get that done today but best laid plans. Despite the initial lapse of several hours between the episodes of weird heartbeat sounds from the speaker - it now seems to be a constant.

At this point, even if I assume that the subwoofer "went bad" - it seems a very strange time to do so - without any audio input above a whisper - and with my ear pain - but even though I dislike them, I know that coincidences do happen. Just strange that both my ear and subwoofer seemed to overload at the same time, and within at most a couple of minutes after the quake started.

I have run across more stories of strange audio experienced by others in VA that seem to have been timed with the earthquake. I'll be lurking around the VA quake threads -

Magnetism. The speaker is a large magnet...and the minute vibrations from the earthquake set off a type of 'feedback' vibration affecting the overall performance. Thats why the volume control had no effect. It wasnt electrical...it was magnetic in its vibrations creating a sound.