hey man u got pm.... we are stumped. we have tried EVERYTHING (but) different frequencies to see if we are just hitting vehicles peak or what the box's peak and such is. so monday we are going to check from 20hz to 80hz just to see the power output and what db it hits at half volume. we have tried 4 headunits. 16v batteries, 12v batteries. the new 4kws have some crazy protection circuits in them so we are thinking something in our box at our freq is making the amps not like it. so we could be playing too low or too high. who knows right now... too many variables