One thing I've learned about pro sound... no two systems are ever the same. Doesn't matter if you have the same reciever, amp, processor, etc. Wiring and location have a whole lot to do with a lot of things. A problem that may not even be audible on his system might be added to by some EMI and produce what you have.

 

I hear a hiss at high volumes sometimes, but it might be because I'm listening to MP3 encoded CDs. I'll pop in a store bought classical CD tomorrow and check again.

Oh yeah, did you check to see if the problem existed with the engine off? It might be because of the alternator whine or something like that.

 

i thought it was my mp3, so i put in an original music cd and the result was the same at high volume. i don't know if the problem exist with the engine off, i will try it out later. if you have the same problem as me, it might be because of infinity speakers, if u already had ground wire to the nagetive on the battery and wired the tweets correctly.

 

To me it sounds like you are hearing your system's THD.
Not a whole lot you can do about it besides what these guys have been telling you.