Ok I ordered these dynamate square rubber thingies that are suppose to be installed behind the sub
I have spare dynamate should I lace the walls with dynamate?

 

Actually, those are supposed to be installed behind your door speakers, not inside of a sub box.

EDIT: Nevermind. I just did a little more researching and found that it can be used inside of sub boxes but I've never seen anyone use that stuff inside a sub box. You're better off with polyfill inside a sub box as far as standing waves go. I would only use those pads behind the speaker inside of a door though. Just my .02.

 

Personally I never put anything in my enclosures. Polyfill is used to reduce standing waves and to "trick" the sub into believing the enclosure is slightly larger but...... As far as those dynamat pieces go? My opinion......marketing hype.

 

I agree. I think it's effective if you put it behind the door speakers as mentioned but then there's cheaper alternatives like closed cell foam.

 

Agreed, But also never put Dynomate in a box, the rubber ones are fine, it will take away if you do;(

 

The waves in the sub range are longer than the length of the car. It is physically impossible to have standing waves in a sub enclosure. Polyfil slows the rear wave by converting some motion to heat and thereby making the enclosure seem about 10% larger when you use 1 pound per cubic foot of stuffing.

The dampening pad installed will take up a small amount of air space. It will also lower the resonant frequency the back panel vibrates at. You want to either raise the resonant frequency or lower it outside of the sub's passband.