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Polyester Fiber Stuffing

Make your subwoofer think it's in a bigger box (1-pound pack)

55 Reviews | 7 questions - 18 answers


Our take on the Polyester Fiber Stuffing

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.

It's stuffing. Works great for stuffing sub boxes, 6x9 boxes, your mom, whatever your heart desires. Adds a crisp clean sound

Cooly, East Troy, wi

What's in the Box:

  • 1 pound of Polyester fiber stuffing

Polyester Fiber Stuffing Reviews

Average Customer Review(s):

(55 Reviews)
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Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

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. [ Danen  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: [ 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 ]

7 questions already asked

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 ]
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 ]
The Polyfil is made of Polyester which is not flammable and does not ignite easily. I hope that helps. My Bio: [ Ryan  Jan 06, 2017 ]  Staff
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 ]
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
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 ]
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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