I have a Pioneer DEH-P580MH headunit with sub output through a 3rd set of RCAs. I will be running a 4 channel amp with 2 channels bridged to a sub and 2 in stereo to the front stage.

Okay, here is where I thought that I'd get all crafty. I used a 3 Channel RCA to the trunk (from home audio) to cover the 3 channels of output that I would have.

I cannot figure out whether or not I can make the HU's sub output mono (thus combining the L&R channels). As of right now, it seems like my mono sub is only hitting in conjunction with one side of the car- L or R, depending on where I have the RCA-out plugged in.

I have several questions-
1. Does anyone know whether I can sum the RCA output WITHIN the HU so that the signal sent through EITHER channel of the sub output has the same (summed) signal?

2. If not, can I run "Y" cables from both channels of the sub out into the single RCA run and then "Y" it back out to both channels at the amp? Or will this short something out?

3. Am I just an idiot who needs to run another RCA cable to the rear and be done with it?

 

You can use a y cable, that should be fine. The only issue I see is that in time there may turn out to be a problem with the sub out. The pre-outs from Pio's do weird things sometimes....

I do think the best decision would be to run the extra rca.

 

I am calling Pioneer to just ask them...

 

Well, I cannot sum the output electronically, but I CAN use a 2M to 1F "Y" on the HU end and run it to the mono input on the amp end.

/thread.