MMC6500 Blown Crossover

[Dobro]

Recently had a local shop install a set of MMC6500 powered by Infinity Reference 475a (75W x 4) and an aftermarket head unit. Sound quality was decent, but tweeters were too bright and hearing engine rpm's slightly through speakers.

While driving the other night, the speakers freaked out and made a deafening high-pitched squealing. I turned down the volume and detached the head unit faceplace, still hearing an amplified engine sound through the speakers. Smelled burning electronics and had to pull over and kill the engine to make it stop frying.

Upon inspection it turned out one of the crossovers had fried. I suspect the installers messed something up, maybe with the single/dual mode switch on the crossover or maybe the amp settings?

Any suggestions on how to troubleshoot the problem? And how do I get a new crossover to replace the fried one?

Thanks,
Dobro

[MacLeod]

Since you heard an alternator whine, that shows it was not a faulty crossover but a wire that was shorting to ground somewhere. More than likely a speaker wire that was touching metal somewhere either at the termination point of the speaker or crossover or where some insulation was stripped off by rubbing against some metal. Either way, its the fault of the installer so I would take it back to the shop and let them make good on it.

And just FYI, this is the home audio section of the forum. For car related stuff go here --> http://www.polkaudio.com/forums/forumdisplay.php?f=5