disappointed with polyfill

[M@nJo 10+ year member]

i have two JL12w6v2's in a small/medium sealed box and decided to give polyester fiberfill a try (bought from walmart). i throw in just enough polyfill til it barely touches the magnet of the woofer (which is estimate .3lb per chamber). this is the loose fill and not folded up ones sold on crutchfield. first thing i noticed was that i lost some SPL. without the fill, i would play a specific track at max volume and it would make the subs hit hard enough to fold down my rear view mirror on loud bass hits. after the fill, i didnt get that effect nor did i feel an audible difference. i know it says 1lb fill per cubic ft but if i were to pack anymore, the fill wouldve been rubbing the magnet/sub coil easily...which i heard to avoid doing to prevent the fill burning from the voicecoils of the woofer.

it seems like everyone had success with polyfill besides me. could somebody tell me what i did wrong?

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[Wowimzz 10+ year member]

is the current enclose too small for the woofers? IIRC you use polyfill to make the woofers see that they are in a bigger box. If your box is already in spec then adding in the polyfill to make the box seem bigger would give you this effect?

 

[M@nJo 10+ year member]

i am not too sure on box specs, but i do know the exterior dimensions:

W-27"/H-14"/D-13.25" with split chambers. 3/4mdf wood.

previous owner wasnt too knowledgeable (like me:blackeye: ) about the box when i purchased these subs. he told me they were an JL box but i doubt that. i could take pics if it helps.

 

[ssj2xxgotenxx 10+ year member]

Well polyfill is just added insurance, it's not going to make a night and day difference. Besides, polyfill is like 2 bucks.. who cares if it doesn't work.

 

[coolahan 10+ year member]

i thought you were supposed to stuff the hell out of the box with polyfill .. //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif

 

[GemaRastem 10+ year member]

polyfill is used for 2 reasons, to make the box seem bigger to the woofer. And to stop the backwave from hitting the subwoofer and distorting it. Sometimes you will gain efficiency, sometimes you will lose it. Seems like this time you loss efficiency, and if you can't tell a difference in sound quality, then take it out. Usually polyfill helps with sound quality a lot though.

 

[coolahan 10+ year member]

polyfill is used for 2 reasons, to make the box seem bigger to the woofer. And to stop the backwave from hitting the subwoofer and distorting it. Sometimes you will gain efficiency, sometimes you will lose it. Seems like this time you loss efficiency, and if you can't tell a difference in sound quality, then take it out. Usually polyfill helps with sound quality a lot though.

he didn't use enough

 

[Volenti 10+ year member]

Polyfill changes the Q of the enclosure via resistive damping. The thermal effect that makes the woofer think it's in a larger enclosure is mis-understood and mis-reported all over the net, it's a subtle, barely audiable change that's completely swamped by the damping properties of fill.

The change that ManJo heard was because he lost almost 3db off the peak of his subs response, the fill damps the motion of the sub like the shocks on a cars suspension damps the motion of the springs.

Adding more will simply increase the effect (up to a point) Fill is a SQ tweek that tends to smooth out a subs response at the cost of peak SPL, it will never, ever, ever make a box louder.

 

[xtremekustomz 10+ year member]

Polyfill changes the Q of the enclosure via resistive damping. The thermal effect that makes the woofer think it's in a larger enclosure is mis-understood and mis-reported all over the net, it's a subtle, barely audiable change that's completely swamped by the damping properties of fill.
The change that ManJo heard was because he lost almost 3db off the peak of his subs response, the fill damps the motion of the sub like the shocks on a cars suspension damps the motion of the springs.

Adding more will simply increase the effect (up to a point) Fill is a SQ tweek that tends to smooth out a subs response at the cost of peak SPL, it will never, ever, ever make a box louder.

Ahh..you beat me to it!

 

[drifterman33 10+ year member]

So what happens if you put to much polyfill or if it is touching the woofer??

 

[05fronty 5,000+ posts]

i have put some in my ported box and it gave me 10 db more.j/k

 

[60ndown 10+ year member]

Polyfill changes the Q of the enclosure via resistive damping. The thermal effect that makes the woofer think it's in a larger enclosure is mis-understood and mis-reported all over the net, it's a subtle, barely audiable change that's completely swamped by the damping properties of fill.
The change that ManJo heard was because he lost almost 3db off the peak of his subs response, the fill damps the motion of the sub like the shocks on a cars suspension damps the motion of the springs.

Adding more will simply increase the effect (up to a point) Fill is a SQ tweek that tends to smooth out a subs response at the cost of peak SPL, it will never, ever, ever make a box louder.

^ **** good explanaton there my brotha!

thankyou.

 

[drifterman33 10+ year member]

So what happens if you put to much polyfill or if it is touching the woofer??

is anyone going to answer

 

[60ndown 10+ year member]

is anyone going to answer

as long as you polyfill is fireproof it doesnt matter, if it is not fireproof there might be a fire.

 

[neonrt 10+ year member]

When i stuffed my previous box, it made a night and day difference, but i used real fiberglass insulation. Stuffed the box as much as i could fit. Now it did not make my peak spl any louder, but it sure as heck helped out my low end.

I used a bunch though. at least a pound per cf if not more.