I looked at a customer's vehicle yesterday that had an odd problem. We installed an Alpine 9847 head unit and Sony 3-way speakers several months ago; also some 12" subs and an amp. What's happening is that when the volume gets to a certain level, the highest frequencies drop out of the front speakers. It sounds like the tweeters are switching off. Turn the volume down, they come back; turn it up, they drop out again. I don't think it's a speaker problem because it happens on both front speakers at the same time (I didn't have time to listen for the problem in the rear speakers).
I was guessing there might be some type of clipping protection in the Alpine head unit that was cutting in, but I can't find any reference to it on Alpine's site. Anyone run into this before?
... my VR series JL comp's do this all the time... its built in tweeter protection... the xover sometimes has a little switch that drops the tweets out when they reach some preset 'overload' point.
Sometimes it was just the right tweeter but usually it was both at the same time.
To my knowledge, that wouldn't be a 'feature' on any deck, especially an Alpine. I'd look more carefully at the speakers instead..
-------------
"I'm finished!" - Daniel Plainview