Does Polyfill from Wal-Mart work?

Back in the old days, we used to use Polyfill from Wal-Mart for our sub boxes and behind our midbass speakers. I wanted to see if everyone still used it or is there something better?

 

Yes it works as long as it's used correctly.

You should use it to effectively simulate a larger box size for an enclosure. Basically, it slows down the airspeed in the box. For a sealed box it will make the speaker perform like it's in a larger enclosure. It does the same thing in a ported box too but with a ported box the tuning will actually drop a couple of hz.

 

Also, unless your midbass are someplace totally dry (meaning not in the doors) I'd suggest not putting it behind them. It will absorb a ton of water back there.

 

Thanks! I am thinking about putting some Polyfill behind my Q-Form Kick Panels speakers.

I assume a JL Stealthbox does not need any Polyfill? (Btw, the Stealthbox might already have Polyfill inside. I have never opened up the Stealthbox.)