Does acoustic foam (egg crate) in speaker box count as space? (1 Viewer)

[JesseSilver]

In other words:
If I have a 3 cubic foot enclosure and line the inside with 1.5" thick acoustic foam, does my enclosure now appear to be something like a 2.5 cubic foot (or whatever the math is) because I just lost 1.5" all around, OR is the foam open enough that it still counts as open space?

Thanks!

 

[Jeremy Stockwell]

Jesse,

I'm no expert, but I believe that not only would the foam stuffing count as open space, but it may effectively enlarge the enclosure slightly. I know that if you stuff the entire enclosure, you get an effective increase in enclosure volume. Lining the sides may have a similar effect to a lesser degree.

JKS

 

[JesseSilver]

Yeah, that was the third unspoken option (and thanks for your reply)! What I'm planning is roughly a 2.5 cubic foot sealed sub with an AV15, stuffed with 3 lbs of polyfill and insides lined with acoustic foam. There will be a Linkwitz transform to push the Q and Fs down, but I was just trying to figure out if the foam effectively increases or decreases the apparent volume. So now we have one vote for increase. Anyone else?

 

[ThomasW]

For all intents and purposes the foam doesn't occupy enough space to be of concern.

 

[Mark Fitzsimmons]

Volume increase.