I have a 2000 Maxima with Bose. I replaced the HU with an alpine and alpine 4 channel amp. I replaced the Bose speakers with Polk 6.5db series; front and rear. The speakers sound horrible. The sound is muffled with no dynamics or imaging. The guy at circuit city said there is a plastic backing, in the doors, and that he could cut them out to improve the sound of the new speakers. Have any of you guys experienced this. I hate to say it, but the bose system sounded much better, and as we all know, it's crap. All I get out of the new speakers is a thump with bad mids. The tweeters are ok. I'm thinking the doors in the Max or tuned for those bose speakers; with the padding and insullation; just a guess. Any feed-back would be greatly appreciated. I'm $1,400 in the hole, and my new system sounds far worse than the bose.

 

Which Alpine HU did you get? My brother just picked one up and it has all kinds of settings for the internal cross over. It's possible that your HU needs to be adjusted so that the line outputs from the HU to the Amp are configured properly for frequency ranges. It seems that you're using a passive cross over between the tweeter and mid/woofer in front. That means that you have to make sure you're sending full range output from the HU to the front speakers. The HU can be configured in such a way that the line outs are not full range but are either sub, mid or high freq. only! That would definitely give you crappy sound.

Check in your manual . . .

 

Did you hook the new headunit up to the factory Bose speaker wires or did you run your own speaker wires? I believe the factory Bose setup has individual amps at each speaker and it's possible that you are trying to run your new amp and headunit through them. I believe there is an adapter from PAC that you can get from Crutchfield if in fact this is the case and you are using the factory wiring. The plastic backing in the doors has nothing at all to do with the bose speakers. Many org members have installed numerous different speaker types in their cars and have had great success. I have infinity Kappa's and they sound awesome despite the fact that I am using a cheap Sony Explod amp.

 

Are you getting a lot of highs and no midbass or bass? If so, the installer may have wired the spkrs out of phase. Like on 1 side of the car, he/she may have hooked up the spkr backwards. Instead of getting a + to a spkr input, it's getting a -. Since you have a 4-channel amp, try swapping the spkr output on 1 side of your front spkrs.