My NU3000DSP thumps....I wouldn't say pops....but it thumps through the subs when powered on with the button.....never tried just the flicking the power strip switch but I'd bet its the same. It's not loud or hard but it happens...Just the nature of the beast? The 6000 is most likely the same.
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find that it was vanity: but the dreamers of the day are dangerous men, for they may act their dreams with open eyes, to make it possible.
T. E. Lawrence.