i have a problem with my car whenever my subs reach the resonant freaquency of my car, the roof jumps about an inch or two. does ne one know of an easy way to fix this

Dude ...you have reached the resonance frequency of your car? What frequency? Just don't pull a Tacoma Narrows episode on the road out there.

Have done Dynomat to your car yet...cut down on the vibrations?

WTF you runnin?

im running two orion cobalt 15'* and dynomat wont work because they are upfiring through the 6by9 holes in my rear deck all the preasure is bouncing off of my back window and to my roof. none of it is being reinforced or cancelled out by the trunk because the preasure is passing straight into the passenger cabin

Tried angling them differently? Is this car in competitions, otherwise that seems a lil loud... Yeah what is the frequency of this car, cause whenever i have money for a subwoofer system i don't wanna set it up at that... Pretty impressive setup btw too. I plan on putting in some nice components and 6x9'* on a 4 way amp next, and then subwoofers afterwards, I'm Going for SQ but some crazy volume is nice too.

if i angle them different i will lose some sound and i might compete with it next year as far as 6by9s go if ur going to get subs neway u might as well leave them out ull get louder and still sound good

I don't like silly overpowering bass. I'd much rather have rear fill speakers, the just full on bass anyways.... If you're going for loudness you should fire them thru the seat opening...

u have to have big drivers if u want to be able to play low freaquencies accurately and the whole reason it gets loud like that is because i turn my car into a practical hatchback with all of the sound compact loading off of my rear window

Man I hear you, Mine does the same thing, guessing not as bad though. At my stereo competion my girlfriend was playing a Bass Mechanic CD and listening to sweeps and I was standing outside, roof was open, and the roof of car is bouncing like 2in. I was amazed that my sunroof didn't crack. she played someother tones and couldn't find waht frequency, went through whole test cd, went back to the sweep tracks and theres my roof juping around. I don't really want to take my headliner down and dynamat. lot of work. I do hear that SQ speaking I hear that you will notice a big time silence when the roof gets done. If it'* bad, you have no choice to dynamate everything, not talking one layer, take apart the rear deck and put 2-3 layers there and work your way up, I say if you got it all apart, might as well put 2 layers and 3 were you need the most reinforcement.

Caution-One bad thing I did was put 2 layers on the top part of the rear deck and it rose the whole carpeted trim plate and made it touch the glass in the back, alloying for a nice rattle suprise after all my dynamating. First I put two grey screws in it to hold the read deck together tight and put a thin piece of foam rubber as a spacer along the rear glass and all the way around the rear deck trim piece, to stop any chance of audiable vibrations. Good luck. Spent many hours seating in back seat pushing on things to "find the rattle" still have a couple to go.

Yeah but that sunroof is probably helping you in terms of flexability....