OVERVIEW

The sound wave coming off the back of your subwoofer reacts with the air contained in the box. Polyester fiber stuffing slows down sound waves inside the box, making the subwoofer perform as if the box were bigger. Use 1 to 1-1/2 pounds of stuffing per cubic foot of box volume.

What's in the box:

Polyester Fiber Stuffing owner's manual

1 pound of Polyester fiber stuffing

REVIEWS

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Polyester Fiber Stuffing Reviews

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Researched by Crutchfield's Mark G.

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Q&A

Q

Crutchfield asked: Why did you buy this?

Never used this before, but reviews were really good. [ Emmanuel Mar 04, 2019 ]

Just want to fill in any available space in the box so I can get maximum speaker quality. [ James Feb 27, 2019 ]

The staff know what I needed. If your not sure take a moment and do a chat with them. [ Brinz Feb 16, 2019 ]

I have a small subwoofer box [ Harry Feb 12, 2019 ]

put in subwoofer enclosures to make subs think they are in larger enclosures. [ MICHAEL Feb 06, 2019 ]

I need it (?) [ Somarie Jan 26, 2019 ]

Calvin told me too lol. I needed this to make my box think its bigger since there isn't a box with my cubic air space. [ Danielle Jan 17, 2019 ]

suggested by tech adviser to adjust airspace inside subwoofer box to match the selected speaker. [ Eric Jan 05, 2019 ]

Hoping it will help with volume in my small custom boxes in my truck mounted sub system. [ Jonathan Dec 18, 2018 ]

No idea I guess for behind the speaker in the roll bar [ JUAN Dec 17, 2018 ]

Suggested [ Michael Dec 08, 2018 ]

god for sub sound [ RYAN Nov 26, 2018 ]

Polyester fiber in a sealed sub enclosure will slow sound waves inside the box against the back of the cone creating a clearer bass wave, making better sound. [ KYLE Nov 24, 2018 ]

Building a sealed subwoofer box. [ Paul Nov 21, 2018 ]

I chose this to fill my factory subwoofer box to help with bass [ TIMOTHY Nov 19, 2018 ]

Well I'm thinking since it help some ppl it might help me too and I can send it back if there's no difference [ H Nov 16, 2018 ]

Because I want my bass to sound as clean as possible. [ D Nov 05, 2018 ]

i made a small subwoofer box and i read that this can help keep the bass frequency low in a smaller enclosure. [ Luis Nov 01, 2018 ]

Wanted to try it out [ Chandler Oct 16, 2018 ]

none [ RALPH Oct 07, 2018 ]

Try it out good reviews [ Skyler Oct 07, 2018 ]

To insulate the interior of thee enclosures being built. To help stop standing wave or interior cancellation issues. [ David Sep 16, 2018 ]

Better sound [ Philip Aug 30, 2018 ]

For a sealed speaker box. [ Jonathan Aug 27, 2018 ]

For a factory sub box [ Clinton Aug 25, 2018 ]

Not a bad idea, stuff usually has good reviews, so why not try it. I don't have filling in another vehicle where I built two custom 8" sub boxes. [ Vernon Aug 15, 2018 ]

I know it's not required to use the stuffing but I desire the best sound possible. [ Bradson Aug 13, 2018 ]

For my sub box [ GORDON Aug 08, 2018 ]

Game my subwoofer box. [ N Aug 04, 2018 ]

My sub box has 0.61 cubic feet of space and the JL subs I ordered need 0.65 cubic feet. This stuffing will make it seem like the box is bigger and make up for the 0.04 cubic feet my box doesn't have [ Jamie R. Jul 21, 2018 ]

to install in sub box [ David Jul 07, 2018 ]

to cut back on vibration [ Jeffery Jun 28, 2018 ]

to help my subwoofer out [ Francisco Jun 25, 2018 ]

Tech Support [ Jeffery Jun 21, 2018 ]

Built a custom sub enclosure. Based on recommendations from many articles and websites, need to add poly-fil. [ John Jun 11, 2018 ]

Recommended by Crutchfield [ Philip Jun 04, 2018 ]

Poly-fill increases the perceived size of your subwoofer box. When building a subwoofer box for a tight area, the fill gives you a little size boost you may not physically have. [ SCOTT Jun 02, 2018 ]

Better sound [ David Jun 01, 2018 ]

Heard good things about stuffing subwoofer enclosure with poly. [ STEVEN Jun 01, 2018 ]

Adding to rollbar and factory subwoofer to hopefully clean up the sound a bit. [ Joseph May 27, 2018 ]

I have a sealed box and polyfil will slow down sound waves and trick the sub into thinking the box is bigger [ Michael J. May 25, 2018 ]

To put in my sound bar on my Jeep [ Danny May 21, 2018 ]

Hogan the advisor suggested it. [ ERNESTO May 19, 2018 ]

Suggested by customer service [ Jerad May 16, 2018 ]

I have a small custom made box and I want to see if this will improve the sound. [ Jazz May 14, 2018 ]

Have a small compartment where the sub box going in my slingshot this will make it sound deeper bass [ pedro May 13, 2018 ]

It's the baddest of the baddest man killer dude [ James May 11, 2018 ]

Supposed to make subs sound better. Decided to give it a try [ JAMES May 08, 2018 ]

Cause my bx was to small [ Kason May 06, 2018 ]

Your advice [ Jeremy Apr 20, 2018 ]

To put in my subwoofer boc [ DERRICK Apr 17, 2018 ]

To minimize vibration [ Charles Apr 15, 2018 ]

subwoofer enclosure [ James Apr 12, 2018 ]

Improve the sound of my sub in the small factory enclosure. [ Bryan Apr 12, 2018 ]

I am hooking up teo amps and I hope this make it easier. [ Raymond Apr 12, 2018 ]

Seems like the cheapest best thing for sound dampening. [ Brent Mar 29, 2018 ]

MORE BASS FOR MY ENCLOSURE [ MARQUIS Mar 21, 2018 ]

Stuffing to help give the Sub the response it needs in a box that is right at the bottom of the size limits of the Sub. [ Randy Mar 01, 2018 ]

for use in the sub woofer box [ Kevin Feb 27, 2018 ]

I'm getting a little 8" 300w rms sub and I'm sure I'll need all the oomf I can get [ Troy Feb 22, 2018 ]

I'm buying the best quality equipment so investing a few more dollars to make them sounds their best is a no-brainer. A powerful sub in a small sealed box will sound that much bigger and better with inexpensive polyfill inside the enclosure while retaining the tightness and accuracy that I desire from my setup. [ Noe Feb 22, 2018 ]

Can get this stuff anywhere, it's convenient to have it shipped with everything else rather than go make a trip to the hobby store. [ Frank Feb 19, 2018 ]

Recommended by my custom SSV works box manufacture for my jeep as well for my overhead sound pods. [ Anthony Jan 23, 2018 ]

To make the sub woofers think they are in a larger enclosure. [ MICHAEL Jan 18, 2018 ]

I heard stuffing a subwoofer box with this is a cheap upgrade to the sub's performance. [ Tyler Michael Jan 05, 2018 ]

Better sound [ Liseth Dec 18, 2017 ]

Cheap improvement in sound quality [ JOHN D Dec 16, 2017 ]

I used box "stuffing" in portet box years ago, now I have sealed box, however Crutchfield says it improves areal woofer performance... [ Gary Dec 10, 2017 ]

Wanted to make sure the subwoofer sounded as good as possible. Fill might be degraded or old in the current stock box or not even there. [ BRIAN Dec 06, 2017 ]

sub box was too small [ Lisa Nov 30, 2017 ]

To make it sound better [ SAMSON Nov 16, 2017 ]

I chose the fiber stuffing because it states "make your sub feel like its in a bigger box" which I assume means it will have a better sounding bass. [ Brydan K.D. Nov 03, 2017 ]

Fill for factory subwoofer enclosure. [ John Nov 03, 2017 ]

better sound [ B Oct 13, 2017 ]

To receive cleaner sound from my custom speaker enclosure [ Micah Sep 21, 2017 ]

fiberfill makes the speaker think it is in a larger enclosure. [ MICHAEL Aug 22, 2017 ]

fill for subwoofer box [ DAVID Aug 15, 2017 ]

Reliable and good price. [ G Aug 11, 2017 ]

Improved cleaner deeper sound! [ Bannon Aug 09, 2017 ]

Needed for sound [ STEPHEN R. Aug 05, 2017 ]

Just to try. [ MICHAEL Jul 03, 2017 ]

It was highly recommended by other customers based on their reviews. [ Jose Jul 01, 2017 ]

For my sub box I already have [ Kory Jun 16, 2017 ]

Recommended [ joshua Jun 13, 2017 ]

I needed it for my new sub and box for my truck. [ Lonnie Jun 12, 2017 ]

Seemed like a good idea [ robert May 17, 2017 ]

to make a small space seem bigger [ shane May 11, 2017 ]

More boom small box [ JASON Apr 26, 2017 ]

for subwoofer box [ RICHARD Apr 25, 2017 ]

I chose this item because it is a great addition & I haven't been offered a convenient option to fill an empty speaker mount void before. [ Hanssel Apr 22, 2017 ]

Purchased new Sub Box... it did not have stuffing with it. .so I purchased this fiber stuffing for the new box..... [ TIMOTHY J Apr 12, 2017 ]

I was watching an upgrade video on YouTube and they recommended using this in the front install as there's a sound difference between the sound bar and the front without it. [ Jonathan Mar 12, 2017 ]

Thought I would Try it Heard good things about it. [ M Mar 03, 2017 ]

It was recommended after I added two subwoofer to my cart. [ Michael Mar 02, 2017 ]

Better sound! [ belkis Feb 22, 2017 ]

to make my speakers sound bigger and deeper [ Michael Feb 09, 2017 ]

Box is right on the edge of having the min space for subs [ Dominic Dec 27, 2016 ]

Needed this for my subwoofer upgrade. [ Raymond Dec 21, 2016 ]

to see if it helps with sound quality [ rodney Dec 17, 2016 ]

Makes the subwoofer feel like its in a bigger box by slowing down sound waves. A must [ Kent Dec 12, 2016 ]

I chose this to help with the sound of my new sub woofers since the box i had was so small. [ John Dec 02, 2016 ]

going to build a small sub box, [ Paul Nov 25, 2016 ]

To improve the bass response of my sound bar speakers. [ Robert Nov 25, 2016 ]

I just want to try it out ! [ Kurt Nov 23, 2016 ]

to enhance my speaker sound that goes into small OEM housing [ Yoon Nov 07, 2016 ]

Crutchfield stated it made your subwoofer think it was in a bigger box. [ David Oct 14, 2016 ]

I have a two similar set ups with 10" subs, I notice the one with the stuffing sounds better then the one without it. [ Ignacio Oct 10, 2016 ]

Wanted to see if it would the bass tighter and more responceive and the results of this stuff blew my mind my subs sound 100 times better. [ Kyle Oct 06, 2016 ]

To get better sound out of my subwoofers. [ Dennis Sep 13, 2016 ]

To use in a Select Increments center console [ shawn Aug 25, 2016 ]

Putting Mid-bass speakers in door pods that aren't quite up to air volume specs. Hoping this material will help the sound and protect the speakers. [ DanenG Aug 14, 2016 ]

This item really helps make your Sub Woofers in your Sub box's sound so much better. I recommend this minimal investment to anyone looking to get better sound out of there system. Sincerely, Sean [ Sean Jul 31, 2016 ]

I owned a 12" Kicker solo baric L7 and I fitted it firstly without the filling into a ported box and it was good, but then I tried it with the filling and the difference in depth and clarity of notes was very noticeable. I recommend to anyone who cares about having a solid sounding system to fit there box with this. [ Mikhail Salter Jul 25, 2016 ]

Because it works...i still have 2 12"Kicker Comps in a box that i purchased from Crutchfield 1996!!. Will use this fiber stuffing to put into the door subs area in my 2011 v6 Mustang:) [ JEFFREY Jul 21, 2016 ]

Small sub in a small box, chose stuffing to increase its sound quality. It did the trick, and was fairly easy to handle. A little linty, but that's to be expected. Recommended. [ Todd Jul 12, 2016 ]

I read in your site that make the sub thinks is in a bigger box, thanks for the good info. [ LUIS Jul 06, 2016 ]

Used to fill a sub-woofer enclosure. [ Albert Jun 30, 2016 ]

Based on tech recommendation. [ Maurice Jun 16, 2016 ]

Used to fill excessive air space in sound bar on wrangler jk [ tim Jun 15, 2016 ]

i remember as a kid that setting my "boombox" on a pillow or cushion of some kind would make the bass sound much warmer, clearer, and louder. The thought of just tossing my sub in a hollow wooden box seems inferior to a well insulated box. [ Christopher Jun 12, 2016 ]

increase the perceived box volume. I don't have that much space [ Dustin Apr 28, 2016 ]

Had a less than desirable amount of space in my sub box. Using this on a reccomendation from Hogan to help combat my small space issues. Hogan's Bio: http://www.crutchfield.com/Support/Bio.aspx?bio=122 [ Ben Apr 04, 2016 ]

To get a better sound [ Shaunathan Apr 03, 2016 ]

The speaker box i built was slightly smaller and the stuffing will help with the woofer and the quality of sound it will produce. Hopefully enhancing the bass. [ Will Mar 02, 2016 ]

I want my subs to sound better [ Andrew Jan 31, 2016 ]

I built a sealed, square box for a new re audio sub. I bought the polyfill to line the enclosure and eliminate standing waves. [ Nicholas Jan 04, 2016 ]

I needed some polyfill to stuff my sealed box. Since I didn't feel like physically going to the store to find it ,I opted to order it from Crutchfield instead. I figured the polyfill found in stores might be less dense (less suited for car audio), so I decided to save myself the trouble and use my reward points. :) [ Gilberto Dec 16, 2015 ]

Have old subs and boxes for pick need 1 cubic foot I'm about 80% hopefully the poly will help or will have make new boxes [ David Dec 10, 2015 ]

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11 questions already asked

How much of a difference will it make if I use 1 lb of poly in a 1.90 cubic foot ported box tuned @ 32 hz ? will the sub think its in a 2.20 and tuned @ 30 hz?

[ Rick55 Jan 09, 2019 ]

My new sub requires 1-1.5 cubic airspace and my sealed box is only .90 cubic airspace . The box fits under my 1997 gmc rear seat, can't go bigger. Will this setup work ok?

[ Charles Dec 31, 2018 ]

3 answers

The stuffing does not increase air space. So no this will not make the box bigger from .9 cuft to 1 or 1.5 cuft. This is best to help reverberating sound waves be knocked down, so to speak, helping the clarity of the sound. Your best bet is to find a speaker that fits the available air space (0.9 cuft) condition

[ bighunt83 Jan 01, 2019 ]

Hi Charles, This is one of those cheap things to just try and see how it works. Poly is used in smaller boxes when the speaker requires more volume.

[ chris Dec 31, 2018 ]

Yes it'll make the sub feel as if it has more airspace

[ Gregory Dec 31, 2018 ]

My new sub requires 1-1.5 cubic airspace and my sealed box is only .90 cubic airspace . The box fits under my 1997 gmc rear seat, can't go bigger. Will this setup work ok?

[ Charles Dec 31, 2018 ]

3 answers

It worked great and made a world of difference with my 15's

[ Erik Dec 31, 2018 ]

Using the fiber stuffing will make the sub think it is in a larger box, and that should make up for the smaller box dimensions you actually have.

[ MICHAEL Dec 31, 2018 ]

Yes it will. You're not going to pack it super tight. It comes in an almost 1 cubic box. When filling you want a consistency of wimpy pillow. You are essentially creating a denser air space inside the the box which causes the inward speaker excursion to be tighter and then the outward movement is freer causing the bass sound wave to explode. Just be sure it is truly a sealed box and not a ported box. I have even used foam gaskets between the speaker and box. The sealed box gives a more natural bass sound than a ported one which is muffled.

[ Michael Dec 31, 2018 ]

Any difference between this stuff and the stuff sold for arts and crafts/stuffed animals?

[ David Mar 26, 2018 ]

3 answers

It's the same stuff

[ john Apr 04, 2018 ]

I do believe that it is a denser material but thought the same thing when I saw the similar material in a craft store. This product did work very well though but you may want to play with the amount of material you use in the subwoofer cabinet to get the right sound before you seal it shut. Hope this helps

[ Richard Apr 04, 2018 ]

Wouldn't know cause I've never used the stuff from the craft store.

[ DAN Apr 04, 2018 ]

What about putting Polly fill in for the back speakers in a Ford ranger? They are 5by7s but are in a very small factory spot behind the seat.

[ Clint May 22, 2017 ]

3 answers

I used the Polly fill behind 5x7 speakers in my motor home and it works great.

[ George May 23, 2017 ]

It certainly wouldn't hurt! Give it a try listen and if you like it, than your done. If not you can always pull the Polly fill back out.

[ Harold May 23, 2017 ]

It won't hurt anything to try it. It's possible you could get better tone out of the low end.

[ SETH May 23, 2017 ]

I have 2 10 inch sub requiring .56 cubic feet per sub, not having any luck finding a box, can I use the poly to fill the 1 cubic foot box to get it close to .56 cubic feet ?

[ Rich Mar 28, 2017 ]

3 answers

When you add polyfill you are tricking the sub into thinking it's in a larger enclosure by slowing the rear waves . It's not used to make enclosure smaller. Hope this helps

[ jacob Mar 29, 2017 ]

I'm not sure it makes a big box smaller, It makes a small box seem bigger. Please ask one of the techs they should know for sure.

[ Roland Mar 28, 2017 ]

Well that is not technically how it works. Polyfill just makes it seem like that there is more air in a box. In order to accomodate for the necessary amount the sub requires. So the answer is a no. Keep looking for a box or switch to a different pair of subs that closely match a box.

[ Juan Mar 28, 2017 ]

Is it flammable or at least resistant? I've had a sub burn out before.

[ Kevin Dec 31, 2016 ]

1 answer

The Polyfil is made of Polyester which is not flammable and does not ignite easily. I hope that helps. My Bio: http://www.crutchfield.com/Support/Bio.aspx?bio=5

[ Ryan Jan 06, 2017 ] Staff

Thinking of putting this in an 8" wedge box with .35 cubic feet. I'll be putting 2 8" RF extreme performance mid-bass speakers in the boxes. Will the stuffing imporove the sound at all or make it louder?

[ Ricky Nov 25, 2015 ]

3 answers

Hi I'm Alan I myself think the stuffing helps make the box not sound hallow or vibrate the box. When you us use the stuffing fluff the stuffing in the box once you have ran the wires to the out side inputs. In general the stuffing makes the bass sound just a bit hard because the subwoofer has back pressure.

[ ROBERT Nov 26, 2015 ]

I've put Poly stuffing in every sealed sub box I've had. Doing so will make your sub perform as if it were in a bigger box. I've found that in sealed applications it produces a harder/punchy/accurate response at the bottom of the frequency range, not necessarily louder. Hope this helps.

[ MICHAEL GREGORY Nov 26, 2015 ]

If you want to use speaker baffling, this is a much better material than fiberglass. Small pieces won't break off that can enter your speaker. That said, adding this material won't make the sound any louder. It typically is used to smooth out the lower frequencies so the music is more natural sounding and less 'boxy or boomy.' Don't stuff the box tight. Use a small amount, pull it to fluff it out, and very loosely fill the enclosure. The effect is more noticeable with larger enclosures with woofers, but even in a smaller box it can make the sound more natural. Hope this helps. Allen

[ Allen Nov 26, 2015 ]

Hi I have a sealed dual box for two 12" subs. Each chamber is 0.78 and my subs require a minimum of 0.65-1.50 cubic ft. I'm trying to get at least a 1.50 cubic ft per chamber. How much stuffing would I need ?

[ David Jan 18, 2015 ]

1 answer

I forwarded your question to an Advisor and they responded with the following: I'd get 2 packs. You may end up with a little left, but this should be sufficient. If you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat.

[ Krissy Jan 21, 2015 ] Staff

Can you use the polyester fiber stuffing with 2 12" JL Audio subs that are in a big ported box? The stuffing won't start coming out of the ports right?

[ Jimmy Jan 16, 2015 ]

3 answers

It works fine in a ported box.

[ Roland Mar 28, 2017 ]

Unlikely to come out the port. Not sure stuffing works well in a ported box though.

[ BRETT May 05, 2015 ]

If you fill the enclosure with stuffing, it should not move. I should also make sure you fill around the port and not inside of it.

[ NORMAN Jan 18, 2015 ]

how do I put this in the box? do I just stuff it in or do I need to like staple it down in the box? thanks

[ david Nov 20, 2014 ]

4 answers

Just stuff the correct amount in the box.

[ STEVEN Dec 03, 2014 ]

Just stuff it in

[ JOHN J Nov 21, 2014 ]

Stuff it! What size box are you using? Used it in a compact box with a 12" Kicker.

[ JEREMY Nov 21, 2014 ]

David, Personally, I did my best to increase the thickness of the stuffing by lightly pulling on it from different directions. Once it was fluffed up, I gently put into the enclosure trying to not to pack it down and loosely filling the inside of the enclosure. You want the sound waves from the woofer to be slow down as it passes through the fibers. If the fiber is packed to tight it will act more like a wall and part of the sound wave could be bounced back to the backside of the woofer casing distortion and possible reduce the life of the woofer. If the enclosure will be moving around, you might want to spray the inside of the enclosure with Spray Mount or some other types of spray adhesives. To keep the fibers from shifting around. I hope this helps.

[ NORMAN Nov 21, 2014 ]

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Q

Crutchfield asked: Why did you buy this?