i have 2 10 in. kickers in a ported box. im havin a problem with the thumb of them i have a 600 watt amp bridged for both tens. i have a hatch back and was wonderin if i should change boxes or get more power to them.. then i have a rhythmic thump. i was wonderin if i could be the amp causin that or if the amp is just under powered.. i have a sony explod deck