I have a Rockford Fosgate R400-D running a pair of Polk db6501 in the front and Alpine SPS-600 in the back. The amp pushes out 75W x 4 RMS (actually 105W according to the birth sheet) The Polks take 100W RMS x 4 and the Alpines take 80W RMS x 4
The HU is a Pioneer DEH-P7200HD with 4V Preamp outs
The first problem I'm having is sound distortion with low frequencies at higher volumes. Any time there is a hard bass hit the sound distorts a little from the Polks but A LOT from the Alpines.
The Alpines were just powered off the HU before for about 2 years so not sure if they were damaged from that, and that's why they distort. The HU only puts out about 14W RMS and those take 80W so not sure if you really can blow them from under-powering them. The volume doesn't have to be up very loud for them to distort either and when they do it makes a loud blaring sound (much louder than the volume of the source material playing) It almost sounds like they are blown, but they play just fine at lower levels.
I have tried adjusting the gain levels on the amp from anywhere between 40-80% and still this happens. Even engaging the HP filter at loud levels the Alpines will make that blaring blown out sound.
My first thought is maybe the wiring...here's how I have it wired
4 gauge RF power wire and ground....dual RCA running from the HU for front and rear, used 9-in-1 scosche wire to run from the amp to factory wiring behind HU (most shops do this so I don't think it's that) Amp is mounted under the passenger seat and appears to have plenty of ventilation and doesn't get hot
A second problem just started today. The sound starts randomly cutting out for a second or 2 at a time and it's completely random, so now I'm trying to figure out what is causing that as well.
I should also say that the wiring for the power cable was reused from my last amp which used to run a sub and got stolen so I know the wiring for that is fine since I had no problems with it before.
It just seems strange that I really can't get much more bass response then I had with the factory unit without getting distortion. I would think by amping up the speakers that I should be getting nice deep bass now.
Any thoughts?
