Please help on 4ch amp setup.

OneOfSun Newbie
Feb 18, 2021
Hi. Thanks in advance!

I have a new Rockford Fosgate T-600 2/4 channel amp that I am having some issues with.

Background / Setup

I am doing a van conversion into a camper. I installed an Alpine ILX-207 as the head unit. I installed two RF (Rockford Fosgate) P3 10" in conjunction with a RF Prime 1200 amp. I ran RF RCAs on the sub, rear, and front lines. I have an XS Power battery dedicated to the audio system (3000 watt max delivery). I have oversized all my wiring. I have two small RF 5 1/4s (?) in the rear door and two Polk DB572 in the front doors, these 4 speakers are wired using factory wiring and are powered from Alpine. I have Leigesaudio distribution blocks fused and non fused for power and ground. The ground block is wired directly to the battery and the battery has another ground run to the frame. I also have a T-Spec 3 micro farad linked to a power distribution block, after my fused power block, that also feeds the RF 1200.

The audio setup was / is working fine with the exception of some high buzz / feedback ( I reduce the gain and the buzz fades, i would like to address this but not the focus of this post).

I then wanted to add the T600 as a 4 channel to feed some more speakers.. but.. First off, the feedback / buzz / hum is ridiculous. Next, it functions fine as a 2 channel and when I switch it to 4 channel I don't get proper sound. 4 channel one of my rear speakers is reduced to garbled low volume distorted translation of the audio.

Speakers are 2) of the Polk DB572 and two RF tweeters PP4-T
PP4-T set on high pass
Polk set on all pass

The two RF RCA lines are coming off the Alpine ILX-207, rear and front. On the Alpine I have sub and rear speakers "on".
I have switched the RCAs around to see if it made a difference, nothing changes.
I have switched my speaker wires around the audio problem simply switches speakers.

2 channel test, using 2 speaker wiring per manual
4 channel test, using 4 speaker wiring per manual

All speaker wire lines are quality, and function fine.

On top of the 4 channel not working there is the hum and hiss coming out, it also makes its way through the sub (more of a warm hum). The grounds are shared for the two amps, meaning they both go back to the same distribution block which goes back to the battery.

The 4 channel thing is really confusing me, it seems straight forward. Two rear and two front speakers. Put positive / negative into corresponding terminals and have on 4 channel and go?

Any thoughts, need any additional info?


Junior Member
May 22, 2013
Pharr, Texas
Any thoughts, need any additional info?
Make sure that Front and Rear RCAs go in, not the Sub RCAs. Put the 2/4 Switch on 4 ch. Turn down Punch EQ and set front and rear to All Pass. I am assuming that the tweeters have built in X-over, if not, set fronts to High Pass. Now test sound and inform us of outcome.

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Most posts - Past 30 days

Latest classifieds