I want to Dynamat my trunk to get rid of those rattles outside as well as my rear deck inside. I have my subs in a sealed enclosure facing the back of the car. I open my armrest to vent the bass through. Now, do I just put Dynamat all over the trunk? I want to put it under the rear deck to stop the rattles inside the car but I'm worried its gonna restrict bass from getting inside. I know the subs breathe through the rear deck because the corners move a little bit when I turn them up. Would it be okay to Dynamat the WHOLE trunk and keep the armest open? Will I still have the same amount of bass?

 

96TL:
Sup man Haven't talked to you in awhile...okay I'll comment your post:

"I want to Dynamat my trunk to get rid of those rattles outside as well as my rear deck inside. I have my subs in a sealed enclosure facing the back of the car. I open my armrest to vent the bass through."

Well there's your first problem...you should have used a ported box, and ported it into the cabin through say...the rear deck. That means no trunk rattle, full bass response (sound pressure wave not having to travel through rear deck and do two material crosses), and no reflective issues...but assuming you aren't going to change that...

"Now, do I just put Dynamat all over the trunk? I want to put it under the rear deck to stop the rattles inside the car but I'm worried its gonna restrict bass from getting inside. I know the subs breathe through the rear deck because the corners move a little bit when I turn them up."

You're totally right...if you have the setup it sounds like...you have a slanted box with the subs pressed up against the rear wall facing the front of the car. The waves go through the rear wall and rear deck, as well as the hole that the arm rest makes. You would not put Dynamat all over the trunk, you'd put it everywhere but the rear wall and possibly rear deck.

"Would it be okay to Dynamat the WHOLE trunk and keep the armest open? Will I still have the same amount of bass?"

Definitely not. The only way that would be possible is if you had subs that somehow were able to direct their air movement to just that hole and nothing else. You don't have that scenario. I'd have to calculate exactly how much you'd lose in terms of the wide surface area of the rear wall being sound blocked by the Dynamat, but in a simple reply...yeah, you'd lose a hella lot of bass there...considering what used to be a huge medium has now been reduced to that pathetic 15"x7" or so hole that is the armrest. You're going to get some trunk rattle no matter what, because you've got subs pushing air around and creating states of high and low pressure, thus pushing the trunk panels in and out. This can be muffled somewhat by Dynamat, but with sufficient power on those subs, you'll never get rid of it in a sealed enclosure like the trunk (unless you make it unsealed by taking out the whole rear seat, or drilling nice 1" air holes all around your trunk)...unless you port your box into the main cabin, thus not allowing the waves to bounce around in there...

Austin519

 

Yeah thats the setup I wanted. I cant have that setup because of the way my trunk is designed. There are 2 stress bars that wont let me push the box back enough to port it through the rear deck. My box is about 1 foot away from the rear wall (rear of backseats) and I think thats already effecting my bass.


Thats exactly the setup I have except the box is about 1 foot away from the rear wall.

So is it worth it for me the Dynamat anything? It doesnt even sound worth it so far. My rear deck rattles like crazy and makes my system sound horrible. I dont know what to do. If I Dynamat everything except the rear wall and rear deck, would that make some more bass?

 

96TL:

It IS worth it...because it will get rid of some rattle, and get rid of the reflective waves within the trunk. Just don't expect it to be dead silent . You may want to rebuild your rear deck...ya know, out of something a bit stronger...say fiberglass...1" thick...and bolt that sucker in tight, and seal it all the way around. Doing the Dynamat won't make MORE bass per se...but (and you'd have to run it through a modeller to be sure)...it will definitely kill some reflective waves, which I bet are giving you some harmonic interference and thus screwing up your incident signal.

Austin519

 

Austin ------- what about taht ported stuff u be talkin bbout -- hows that work splain more

 

TommyBoiSxty9:
"Austin ------- what about taht ported stuff u be talkin bbout -- hows that work splain more "

Okay...easy enough. Say you have this 4th order bandpass box (normal bandpass)...or you have a 6th order box (imagine the subwoofer in a box with a compartment on the front and back that's only opening is a port)...then all of the sound will be going through the ports, and the ports alone. Unlike a normal ported box, or sealed box...where sound is also coming from the speaker cones. So all you have to do is direct the ports of the bandpass up through the rear deck....and thus none of the sound ever even enters the trunk of the car. It just gets dumped into the cabin. So you don't have these problems with a vibrating trunk, or the bass cancelling out because of reflection in the trunk, or having to open the trunk or anything...simple solution that produces MUCH better results...

Austin519