Too much hiss from speakers, what to do?

As far as the excessive rca cables causing hiss that is doubful, but it can pick up other kinds of inducted noise, you might want to move those cables around and listen for changes.

The odd part about your post is you are now using a unit with more preamp voltage but claim you need to set the gains higher. Kind of defeats the benifit of the higher voltage as that if anything should allow a better s/n ratio, as hiss is a byproduct of a poor (or lower) s/n ratio. However the output voltage rating is not the s/n rating. Without knowing the specific s/n ratings of each unit (which I don't) I can't say for certain that this is or is not the problem.

You might also be sensitive to certain frequecies that you didn't notice with the pionner, you could try adjusting the eq settings on the kenwood and lose or lower the hiss to an acceptable level without sacraficing too much SQ.

Best of luck.

While the noise you hear could be caused through your RCA cables, this is unlikely.  Much more likely is improper gain setting or poor quality ground, or a poor ground inside the head unit.  Make sure your RCA cables are not damaged and are properly seated.  Read the ground stickies at the top of this forum and make sure you have good grounds for your amps.  Run a separate ground for the HU (do not use the factory wiring harness ground.)  In fact, some times the best results can be had if the HU and the amps are grounded at the same point.

It is also possible that the new HU is simply noisier than your old one.  If this is the case there's nothing you can do about it other than change the HU.

I doubt a line driver would help you at all.  It also sounds to me like your gain is way too high.  How did you set it?

many factors could be your problem.

"Much more likely is improper gain setting or poor quality ground, or a poor ground inside the head unit." Dyon is on the money, start there first.

i disagree with some ideas though through personal experiance. Rca's can pick up noise-and fairly easily.

" about 8-9ft too long, and I wrapped up around itself and set it on top of the brain unit under the passenger seat"  there is a couple "no no's" here. your rca's should never be longer than you need them. (i actually cut mine down and resolder and heak shrink to my cars length". since you wrapped them up and there so long they could be picking up inductance and acting like a coil (providing unwanted resistance). it's possible but not likely you could be picking up noise from your brain as well, but not likely. also make sure your RCA's are not running next to your power wire as this will pick up alot of noise as well.

hopefully if you take these easy steps it will clear up your problem. if not let us no and we can help you further. good luck.

The markings on the amplifiers are really meaningless.  Did you use test tones?  Did you set by ear?  Did you use a multimeter as JL Audio suggests?  Or did you just guess?  I really bet your gain is high and this is exaggerating any noise in your system, if not introducing it.  And I still bet your HU ground is bad.