[smd-dd1 shows clipping with music?]

I'm having problems with my dd1 and i have a kenwood head unit i couldn't get the signal light to come on whatsoever i tried numerous things but you're saying you only got yours to show a signal if you turned the sub level to +15? my only concern about doing that is would i be maybe overpowering my sub? but would the gain level just compensate for the high sub level of the head unit?

[Ground]

Is it absolutely necessary to ground the dd1 on the amplifiers ground. i would have to take my car halfway apart to get there is why i ask.