OK so just incase that subject line was too confusing, this is what i would like to do. I'm looking into a custom box for my 06 that basicly cuts the trunk in half and leaves more or less no room around the edges from tom to bottom and left to right. The thing fits snug.

I would like to mount the subs inverted but firing towards the rear of the trunk, having the subs actually in between the enclosure and my rear seats, which i will eventually delete.

MY question is this, what would happen if i lined the back wall of the enclosure with dynamat? To clarify, im talking about the inside back wall facing the mounting holes for the subs. Would this block the sound from going past the enclosure to the trunk opening and keep it towards the cab? Or would it possibly reduce the baffle of the rear part of the enclosure and eliminate the sound completly?

I dont know too much about how dynamat works but i think the concept is to add mass to help reduce vibration at audible frequencies. If this is the case then wouldnt it prevent the sub box from resonating and creating that rediculous bass that we love?

 

I dont think it would do much of anything

 

it will help keep the back part of your car from rattling.

 

my main goal is to eliminate the rattle in the trunk and kill that backwave that causes distortion

 

would polyfill or some kind of foam have the same effect of sound deadening from that backwave?

 

polyfil will slow the air speed slightly inside the box. That gives you slightly more volume by "tricking" the sub into thinking it is in a larger enclosure. If you are trying to keep sound in the trunk, dynamat the trunk.

Ideally, the reason sub boxes are built so heavy and rigid is to elinimate any vibrations of the enclosure. If you are having problems with box flexing brace the box internally.

 

the idea is to keep the sound from getting to the trunk period, not keep it in the trunk. ive been told that dynamat disperses the backwave from the sub. therefore if it was in the enclosure wouldnt it prevent it from getting to my trunk entirely and keep the sound in front of the enclosure and the front of the car?

 

If your box is sealed properly and is not a vented enclosure the backwave will be held into the box.

Some of the backwave could be transmitted through the enclosure to the trunk and in that case you would want to deaden the trunk so that it absorbs, not reflects the sound.

This is the same premise many people use when making walls. I have never seen dynamat on the interior walls of a well built wall.

In order to keep the sound out of the trunk, make sure you seal the wall enclosures with weather stripping or some sort of other sealer.

Also, make sure you have a place for the waves to enter the cabin. If you have any sort of rear shelf speaker, take them out.