I was almost happy with the stock set up when I ran a taller shield(stock), so I'm gonna say shield height has some to do with it. I have an ARC set up now with the 5.25 speakers and am thinking of going to the 6.5. I do like the set up I have now, I does well till about 70mph or so. I am running the KW 12" and I either don't wear a lid or have a 1/2 beanie. With all the wind rushing by the ears it makes it hard to hear the tunes.

 

Maybe I need to lower my expectation of what this system is designed to do. However, I see a bunch of posts saying how great their systems rock at 70-80 mph. I would just be happy to hear the music clearly (regardless of bass) at that speed. However, You would think that for $500+ for an amp it would drive the **** out of a pair of speakers...

 

I have the psc 1504 same unit just expandable to 5 channels. It will absolutely rock and be clearly heard at 80. We do lots of touring just got back from a 2k miler. While on major roads we generally run 75 to 85 and we do not, repeat do not run at full volume. I read in your post that you used the radio to set the gain from what I remember you must use a store bought cd which has a steady line level input, personally I ran the volume on the head unit at max then adjusted the gain to just under distoration this is past what they recommend but I believe that was the same problem someone had posted about a year earlier. Seems to work for me because I like it loud and clear. Kinda cool comming up to a red light blasting some blues almost like those getto blasters that pi*s me off.

 

Like Carl said, call HW. I've got one in my EGC and this is my second system in as many bikes. Somewhere there's a glitch. I can hear mine easily at 80+.