Laptops :: Light Spillage On MBP Duo - Right Speaker Damaged

My MBP 15" Duo 2.33 A1211 received light spillage. The apparent damage was limited to loss of the keyboard backlight on 3/4 of the panel and, of greater concern, effective loss of the right speaker. Audio does pass, though far too faint and distorted to be useful. The left speaker/channel functions as per normal. Last night I successfully replaced the combined speaker assembly yet the same symptoms remain with no change. My knowledge of the guts of my machine is slight though growing. Where should I go next up the signal chain to trouble shoot? Is there a dedicated audio amp onboard between the logic board & the speakers? Outside of my stated problem, all other hardware/processes have functioned without issue since the accident.