Anyone else notice a BIG difference between the front and rear output from their stock 6.5 HU? I noticed this when I first installed my BT4180 and speakers. I initially thought it was the difference in speakers, I had BT6.5 in the fairing and Alpine SPR 60's in the rear pods. When I faded from full front to full rear the rear sounded way better. Then I swapped my LL at the input making rear fade go to front speakers and front fade go to rear and then the front speakers sounded way better then the rear. Then I eliminated the amp, LL and BO harness going strait from the HU to the speakers and again the rear sounded way better then the front(so it has nothing to do with the new equipment). I decided to run the front fairing(and now lowers) off the better sounding rear HU output and the rear pods off the front so my fade is backwards and was happy(kinda). Then I read that Bill at BT also found the same thing on his and some other customers stock Rushmore head units. Then we figured out that software version 1.19.00 gave a much better sound then the(as of now) two newer updates. I went back to 19.00 and noticed a huge difference. Sunday I was under the lid tinkering and tested the rear and front outputs again hoping the .00 software might have fixed that problem but no luck, rear still sounds way better. So, I decided to run everything off the rear HU plug using only one LL and split the LL output to both sides of the 4180 amp using RCA "Y" splitters. Now the rear speakers sound the same as the front I just lost fade(front and rear are not in parallel still 4 output channels out of the amp) but I never really use it anyway.

Long story short, anyone else notice this? If anyone happens to have their fairing off do a quick test. Unplug both line levelers from HU, take your front speaker LL plug and plug it into each output of the HU plugs and see if you can hear a big difference between the two. I'm curious and if so, you might get much better front stage sound by swapping rear to front or run everything off the rear till this all gets figured out.

 

curious if your voltages are different front and rear.

I just redid my setup again last night, 24.3 +/- .1 to each channel by adjusting the BT355's (using a 600.4)

 

I didn't measure Voltages but testing the HU with a dd1 the front distorted -4 volume bars at 40hz and -2 at 1khz while the rear were -2 at 40 and 0(showed no distortion) at 1khz.