i have a kx2500.1 and 2 fi q's in my car for about a month...all of a sudden my bass cuts out today and then comes back on and my amp goes into protect mode. it seems to only happen when the music is up and the subs are pounding really hard. it sometimes cuts out for like a minute or so and then comes back on pounding again. i checked all my grounds and cant find what the problem is. it seems really wierd that it started happenin for the first time in a month.
the terminal leads could be burning out in your sub due to the amp drawing more current than the alternator can provide causing a clipped signal to be sent to your subs.
Check the voltage at the amp, get it pounding and check it again. Is the amp hot? Did the weather get hotter there lately? Or is it in a cool spot. Are you running recommended ohm load for it and not less?