I never tried this until about 3 months ago when a friend who had W-6's in his truck awhile back said that JL's tend to hit harder in a Ported Enclosure w/ Polyfill stuffed throughout the enclosure. Does anyone know if this is true or not? I have had my 15's in single Ported Enclosures w/Polyfill for about 2 to 3 months and I'm not positive but I think it might be hittin harder but also I have a PPI amp now running these subs when before I had Phoenix Gold XS2500! That could be why also! What do you Fellas think? I have just picked up another PPI PC2150 tonight about an hour or so ago on my way home from work too! So this is my setup now! 2 15's W-6's ran parallel to one PPI 2150, 2 12's W-6's that were on the XS2500 but tomorrow that will change to a 2150 also! All subs are in single enclosures! 1.0 Farad Cap to each amp also! What kind of DB's should I be puttin out? Wish I could find out, Going to sell the Phoenix Gold XS2500 (Have LPL Bass Knob) to a lucky person on E-bay or theres a few friends who might want it! Payed 440 when it came out and have only used it for about a year and 6 months total!

Anyone on here is welcome to make an Offer or inquire on it. I am looking to get $150 w/LPL and 125 w/out. Still works GREAT!!! AWESOMWE AMP!!! Anyone interested shoot me a message! THanks So whats the DEAL ON THE POLYFILL???? N-E-ONE KNOW?

Whats! with! the! exclimation! marks! ?!

It won't help unless your box is too small. However, if you have two 12's and two 15's in the same box you have other much more serious problems.

It won't make it "hit harder." It WILL slightly reduce the FR peaks.

Don't know whats up with the exclamatioins mark! Its easier to reach on a keyboard than a period. For me anyways, thanks tirefyr for the knowledge. No all the subs are in there own enclosures otherwise I dont think I could get them in my trunk! The other thing I was wonderin is where to get a PPI Q-Bass Remote 4 a decent price? Anyone know? thanks It can be used too.

Did you contact PPI ?