pros&cons to polyfill in sub enclosures

[Kfred]

ive heard about people putting poly-fill or foam into sub enclosures. I just wondered what the pros/cons were to putting it in there, also if anyone has already put it in thier own boxes and heard a difference?
Also i heard that it creates heat inside the box...but isnt heat and enemy to subwoofers?
Does it actually make the subs sound better or is this just a waste? I have some leftover from a project and wondered about putting it in my box.
Im running 2-Kenwood typhoons 10" in an MTX box powered by a pioneer 760w amp off of a panasonic HU.

 

[Kfred]

bump?

 

[Anime]

Polyfill is useful in cramped, tight installations where you don't quite have enough volume to meet the airspace requirements of your sub. It can get warm with enough pressure, and with the sub getting warm too, but it won't damage anything, and a decent sub will handle any temps it causes.

The real disadvantage to using polyfill is the way it's sort of a band-aid fix to the problem, and the artificial "creation" of airspace isn't exact, so even with polyfill in a 0.85 cu ft. box, it's never REALLY going to be a 1.0 cu ft. box, and you'd have to do a lot of trial and error and experimentation with different amounts of polyfill to see how much fools that particular sub into thinking it's in the right size box.

So, it's good when there's no other option, and you're just trying to do the best you can with limited airspace. There's usually more creative solutions these days, with both small and shallow-depth subs that have insanely small airspace requirements, and odd-shape fiberglass enclosures that take advantage of every cubic inch.

I wouldn't ever suggest using polyfill just to throw in a box that's already the right size. If it's the right size for the subs, leave it be. If you have a box that's ever so slightly too small and you want to throw it in instead of making a new box, even if you have plenty of room, sure, it makes for an inexpensive solution.

 

[Kfred]

oh, ok. so its not somthing that people use as a sort of "trick up their sleve" to make their subs sound better. i just recently heard of it and i started looking into it and seeing what the benefits were and if i should do it or not.

 

[aznboi3644]

polyfill creates heat thus making the volume of air seem larger to the subwoofer.