PDA

View Full Version : Polyfill for SPL



shizzzon
08-03-2009, 06:07 PM
I've reached a point where cutting off the port length is losing SPL...

The best port length i have is 18" though due to port area size, bla bla bla...

if i keep shortening the port length, port tuning will go up and i start to lose dbs at my peak frequency...

So... if i were to start adding polyfill in the box... would this actually start to lower my tuning AND help me to keep gaining SPL? or does polyfill prohibit increases to pressure?

Louisiana_CRX
08-03-2009, 06:11 PM
i've seen polyfill where it got so hot it actually melted to the magnet of the sub...lol

Pioneer~Saturn
08-03-2009, 06:12 PM
I wouldnt think polyfill would help get louder

ciaonzo
08-03-2009, 06:16 PM
Polyfill gives the driver the impression it's in a larger enclosure than it's actually in.

shizzzon
08-03-2009, 06:16 PM
well, that's why i dont know what will happen.

Either it will lower my tuning which i know it will if used but while lowering tuning to a point where shorter ports will peak closer to my car's peak... will this continue to start increasing spl again as tuning get's closer to car's peak or will the polyfill actually somehow, i dont know how to explain it, just plain prevent an increase in pressure like trying to use a small port area instead of a large one...

shizzzon
08-03-2009, 06:19 PM
maybe i didnt explain enough...

I had a 25.5" port length and i start cutting little by little off until i got the loudest...

My loudest is using an 18" long port...

The only way i can continue to gain spl is by increasing internal volume...

I know polyfill gives this effect. So, by using the same port area, if internal volume increases, tuning decreases as well.

So it's like a win-win situation in my case. I need to keep testing ports but i cant until i take another approach and this is the next one...

killa101
08-04-2009, 05:50 AM
You could cut the port down more after you add the polyfill if you feel it gives you more output.

Polyfill will absorb some energy so you may lose a little SPL. I don't know all the info but the increase in SPL from a larger internal volume may not be very large due to the loss from adding polyfill.

Immacomputer
08-04-2009, 08:43 AM
The only way i can continue to gain spl is by increasing internal volume...

I know polyfill gives this effect. So, by using the same port area, if internal volume increases, tuning decreases as well.

That's not really how polyfil works. It dampens the response, not make the enclosure volume seem larger. Making an enclosure larger can help dampen a response as well but they don't really share any other properties. Polyfil is rarely going to gain you any output as it is meant to dampen peaks and smooth in valleys.

Try it and see though.