I used to have foam egg crate inside of my box but I took it out yesterday because a friend at school said that the egg crate would probably be absorbing the bass and deadening it. I have messed around with a few subwoofers we have in our house for home audio and their enclosures are completely lined with foam of some sort inside of them.
I have always had a roll of egg crate foam inside of my closet because I once slept on it as a kid and that's why I decided to experiment with the stuff. I haven't hooked up my sub yet because I am going to be carpetting the box tomorrow and I figured I could just ask here because I'm sure some of you have experimented or heard about foam being in boxes and the effect it has on the sound.
I have a blown sub in one of the home audio boxes and I could easily pull the foam out of them and see what it does to my Kicker's box. It isn't very spongy/fluffy, its more of a home insulation type foam. I believe I've been told about fiberfill before, and I'd guess that's what its like, although I really don't know what fiberfill looks/feels like. I just know that my egg crate foam is pretty dry rotted, not to the point where its falling apart, but you could tear it pretty easy, its kind of brittle, although it still is a pretty good cushion.
What do you think different types of foam do to the overall sound of a subwoofer? I have begun to think that the smoothness and SQ of the bass is improved, while SPL is decreased.
Thanks for any comments or opinions