OK, I just finished installing my new system, and it has a few problems. First, I should explain how I've got it set up, as its a little unorthodox :

I have an Eclipse CD3434 HU powering two Alpine SPS-170A speakers in the doors. I disconnected the rear factory speakers. For a sub I reused the factory Bose sub by cutting the rear speaker signal wires (in the factory system, these send signal to both rear speakers and the sub) out of the factory harness, wiring them to a pair of RCA connectors, and plugging them into the non-fader outs on the back of the HU. So far so good, right?

Now here's the problem. When the stereo is on and the engine off, everything is fine. However, when the engine is running, I get a high-pitched whine out of the sub only, not out of the front speakers. I have already checked and this IS NOT alternator noise. The alternator noise, also audible in the sub, is very very quiet at idle and raises only slightly in pitch and volume as the engine is revved. This noise, however, is very loud at idle, and actually goes down slightly in volume as the engine is revved.

The sub also crackles slightly when I push in the brake (I'm not kidding, I've tested it), and pops loudly whenever I change radio stations. These could all be separate problems, or all related to the same thing, I don't know. So far, we've tried wiring capacitors into the power wire just before the sub amp to clean up the current, but that didn't seem to do anything.

Sorry for the long post, but anyone have any ideas?