Passenger-rear speaker pops

Hi all,

I've been reading posts for a while and haven't seen my exact problem. (Might not have looked long enough :)

Here's the details:

'94 Accord LX
Sony MP3 Player
Sony Xplod 6.5" speakers x4
Avital 2300 alarm w/o additional modules

The car has suffered from a break-in where the prev Sony head-unit, amp, and subs were stolen, which was followed by a very poor "professional" installation of the MP3 player and alarm.  I've since re-installed/verified almost every connection to the head-unit and the alarm, but I still have the occasional quirky behavior.  I removed the wiring that used to go to the amp and subs (power, ground, amp-remote, RCA cables, speaker-wires).

The system has been well behaved for about 3 months, excepting an occasional unexplained switch to ATT On while driving, and has recently developed the following problem;

The passenger-rear speaker pops once, (outward, like when testing polarity w/ 9v batt.), whenever the head-unit is powered, the station is changed, or the mode is changed between CD/MP3, AM, or FM. The speaker doesn't pop in relation to a change in volume, ATT going on or off, CD track change, MP3 file change, or D-Bass setting change.  The volume of the speaker pop noise does not change relative to the system volume or mode.  The sound quality is not degraded, the speaker doesn't sound blown when checking with fade and balance, and it seems to be in-phase with the other speakers.  None of the other speakers have popped, and the development of the popping problem doesn't coincide with any time I was working on the car.

I hope it's something simple that I've overlooked, and I have no aversion to tearing my car apart to get this figured out.  There's a lot of car to tear apart :), and I'd like some expert insight/direction.

Thanks for taking the time to read my question, and thanks in advance for your help,

Mike

Sound Pressure,

I ran out and checked the terminals on the back of the speaker; they appear to have good tight connections and the terminals and connectors don't look like they're able to come into contact with each-other or any part of the chassis.  The speaker itself is nice and tight in the rear-deck.  I did a sound-check again and I still can't hear any phase distortion.

I wonder if the speaker-wire is grounding out somewhere else.  How can I check that?  I have a DMM and a test light avail.

Thanks,

Mike