not sure how much it's moving never really check it yet there really no telling when it happen's its all random on the time when it does so i could be sitting for who knows how long before it does but one thing i did not put down is as i turn it down i can still hear the sound but very quite. my gain on my amp is set about little over a quart of the gain so it's not at half way yet. i set the gain on my amp by ear and i watch the sub and listen to it and same with the ssf to when i start hearing the sound change i back it down a bit but never to the point where the sub would clip. so i am not really sure if the sub sound changes at 800 watts or what before it clips since this my first time hearing a sundown audio sub so i did not want to take the chance to find out.