I have a refurb D1 I bought less than a month ago. Well, not sure when it started, but I noticed yesterday when I was working with door speakers that the driver's side is much more quiet than the passenger.

I even adjusted the balance to either side and the left was much weaker, especially in the lower frequencies; my sub didn't make a peep when I adjusted all the way left. The rear speakers have the same effect as well.

It doesn't seem like the amp portion is bad because it'll keep going louder without distortion, it's just not as loud as the right and seems to have no bass when adjusted all the way left (same effect if I shut off the sub, so no, it's not just maybe I didn't plug in the left RCA for the sub).

I'm guessing maybe some misadjusted or malfunctioning small-signal component? Or is there some magical software control that could be causing this?

What kind of vehicle is it installed in? What kind of amps, speakers do you have? Were wire harnesses used or was the factory wiring spliced into? Might be able to help you, but need to know that stuff first.

cntrylvr79 said:

What kind of vehicle is it installed in? What kind of amps, speakers do you have? Were wire harnesses used or was the factory wiring spliced into? Might be able to help you, but need to know that stuff first.

It is in a 2000 Honda Civic. The fronts are a 6.5" Focal component set (tweeter and midbass with passive crossover), rears are infinity 6x9s, cabin speakers powered by the D1, sub is powered by a USAmps USA-300 2-ch amp bridged.

A stock harness adapter was used and connections to D1 harness were soldered.

Ok, I wanted to get some more detailed observations based on some suspicions, so here's what I've found:

The left/right volume difference ONLY happens when I'm using XM radio (GEX-P900XM Pioneer tuner, an older unit), radio and CD are fine. But, the sub difference still happens. I accessed the RCA outs and noticed there was no change in output when I unpluged the left (white) RCA, but only when the right (red) was unplugged. Both are plugged into my amp, so it should still draw signal from both channels to sum for bridged, right? The amplifier manual states that input should be provided to both channels.

Any ideas on the reasons for these things?

How old is the amp? Some of the US Amps had a L/R/sum mono switch, so make sure it is on stereo or summed input.

It is a 1999 model. There are only switches for subsonic filter and crossover, which both are off. I didn't think about it, but I also could try switching the inputs to see if the white one is putting out any signal at all. I'll try it tonight.

And I did try unpluging the output/input harness and plugging it back in, which didn't change anything.

Any ideas on the XM weirdness?

Try another IP-Bus cable, if available. Otherwise try wiggling the connections at the XM unit and the head to see if there is any difference.