Just to clarify, are you sure the "fuzzy" sound is coming from both speakers or could it be just one? I had a similar problem and it turned out that the speaker that was fuzzy was close to blowing. Replaced the speakers and works fine now.
Just swap out a cheap speaker on each side and see if problem persist ... if not you know what the problem is.
Does "fuzzy" sound come from both front speakers? Could have Treble set too high on deck and a "hissing" will happen at low volume. Amp jacks on deck aslo send bass and treble signals to amps. Try turning the treble down a bit.
SOrry for repeat, took a while to get the post through. If both are making noise than check RCA cables or Amp. I doubt two speakers will go at the same time and do so in the same fashion.