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Discussion Starter · #1 · (Edited)
Let me just start off by saying that this is my first post at DIY, and as such I may have put this in the wrong section. Please excuse me if that is the case. I have searched briefly for threads containing a similar problem, but came out empty handed. Nevertheless I may have missed something. If there is another place I should be looking to find the answer to this question, please point me in the right direction.

Now on to the problem:

I just recently replaced my aging Eclipse CD8443 with the newer (and mp3 compatible) Pioneer DEH-80PRS. After swapping in the new headunit, I am hearing a large amount of distortion in the high range at low volumes. The issue was prevalent before with the 8443, but not nearly as annoying.

My System:
Pioneer DEH-80PRS
Polk PA660
Polk MM6501 (Front, tweeters at top of door panel)
Polk DB691 (Rear)
Subs, but those are probably irrelevant for this issue.
Just put in new Knu Krystal RCA's. Ended the alternator whine but not the noise.
Also, the front speakers are wired through the stock harness (Didn't want to deal with running wires into the doors).

Now, ever since I bought the PA660, there has been a pretty noticeable hiss, but every amp has its limitations. The system sounds great at mid to high volume when the signal is complex. Thus, I don't believe that the tweeters would be blown; however, I haven't ever really had the chance to listen to blown tweeters.

Just today I went out to try a few more things. First I turned the gain on the PA660 all the way down. The hiss was still present, and so was the distortion. I would like to say that the symptoms weren't quite as loud, but I honestly don't know for sure. My brain may just be tricking me. After doing this, I muted the front speakers and climbed into the back seat. From this position I could clearly hear the rear speakers, and alas there was no audible distortion such as there was in the front. Could it be that both of the front tweeters are malfunctioning? Or is the noise simply more evident in the front because the speakers are of higher fidelity?

This one has really puzzled me. I have listened to the same music on my Sony 7506's and found no hint of that distortion. And by distortion I mean what sounds like a square wave in harmony with whatever tone is being played. The problem is most evident when only one note is played at a time--say a slow piano solo. Once the song speeds up and the music gets more complicated, the distortion is inaudible, at least at high volumes.

I may try to record said distortion and post it somewhere online for you to listen to, but that could take me some time to figure out. If there is any other information which I can provide you (other than say my ssn) which will help the cause, I will be glad to oblige. Thanks in advance for helping me sort this out.

Edit: I suppose that the added noise could just be because the 80PRS has weaker (5v) outs than the 8443 (8v). But, then wouldn't turning the gain all the way down on the amp have made a significant difference? Hmm..
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