I posted this on FB as well, but not much for replies.

2015 SG, Boom system removed (not sure if 1 or 2 amps) fairing and lid speakers. Stock HU. Not sure what flash (does have fade option, but doesn't work)

I installed: SD 800.4, DB Motos fairing, JL 8.8 lids and ARC DSP (hi-level input with ARC resistors and 2 volt output)

Music sounds like it is being played in a tunnel. Vocals and instrument volumes go up and down, good and bad. Every song different. No bass or volume to music. I have installed similar setups and using close to same DSP settings. No matter music source. Reset HU, no change.

Is this a DSP issue or does HU need to be flashed or something else?

 

The first thing is fade is there but doesn't work tells me that the hu has some flash issues, Rob can probable help with that since he has the tools to re flash the hu.

 

I tested a few different flashes are there was a couple that distorted at about half volume. It gave the music a weird mixed sound. I also had a bad resistor on the arc harness and had to switch to a different input.
I would start with a flash change so you know where you are at and go from there.

 

I did install with Arc Moto 600.4 amp and tried to use HI-LO converter and got same tunnel sound. I'm assuming those resistors in the harness cause this issue. Use new Rockford flash and try again, should help

 

Well flash (4 speaker 0 amp) didn't fix it.