you could always terminate the cables with spades and seal them up with heatshrink. I have seen quite a few peices of various electronic equipment that have come from houses on the water and I think that eventually if you dont have your house sealed up all the time with A/C its kinda imminent. Especially with dust build-up that can accumilate and then absorb the salt in the air. Bad combo
You could also tin the ends of your speakerwire with solder. Not sure if I would try that anti-corrode stuff that electricians sometimes use.
