Should I stuff my cab?

[MesaHead]

i'm building either a 4x12 or a 2x12 and i've seen some older cabs (bassman) that have foam inside.

what's that all about? is it to dampen frequencies or to tighten up the cab's resonance?

can someone explain to me why, and what the foam is used for?

thanks.

 

[Farview]

don't bother with the foam

What they were trying to do was slow down the air that was swirling around in the cabinet. Usually this was done on cabs with ports. If you are building a 4x12 cab to get the same effect as a Marshall, there should be no ports and nothing inside the cabinet.

 

[Fusioninspace]

If it's a sealled cabinet, then foam would help the cab/speaker reach a lower frequency response. They routinely use fiber insulation-like materials in the audio industry to improve bottom end performance of sealed enclosures. It's a way to make the cabinet respond as if it's a larger (cubic foot wise) one.

I personally like sealed enclosure for home audio because they tend to have a much more level bass response... Ported enclosures can get hit somewhat lower frequencies, but they will not have as level of a response.

But for musical instruments, I don't think I would worry about what the audio industry is doing to much. Musicians MAKE the sounds, audio equipment tries to DUPLICATE it.

 

[Clive Hugh]

I find that the sheet insulation or mats are good in a sealed cabinet but wouldn't bother if I was making an open backed one.