Polyester Fiber Stuffing

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

Item #: 027808

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40 Reviews

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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.

Polyester Fiber Stuffing Reviews

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Helps with add that extra cubic feet if your box is to small.

Written By kert, California on Wednesday, April 01, 2015

Crutchfield Customer Review (What's this?)

Had a shallow sub box at .50 cubic feet sub needed .75 cubic feet added stuffing and it made up the deference sub sounds great.

Pros: Great sound and money saving option.

Cons: none

Poly fill is a must for anyone

Written By josh, Orange County, CA on Monday, February 16, 2015

Crutchfield Customer Review (What's this?)

To get the full quality out of any speaker you must use this product. Bass is more full, mids more clear and trebles more rounded. Excellent price and excellent product.

Pros: Easy for anyone to use, great value for the cost

Cons: none

Helps with small enclosure.

Written By Lee, Mayo, FL on Wednesday, January 14, 2015

Crutchfield Customer Review (What's this?)

It seemed to help add a little umph to the sub.

Pros: Ease of use.

Cons: None



Crutchfield Customer Review (What's this?)

For the bass your looking for, you need 3 things a great woofer, box and this polyester fiber suffing.

Pros: Tight bass, better quality sound

Cons: Expensive


Written By Karrmike, Orlando,FL on Monday, December 08, 2014

Crutchfield Customer Review (What's this?)

I got 2 12s 1995 Pioneer Impps in a sealed enclosure and let me tell you I had to double up on the dynamat after putting this in the box! I ordered 2lbs one for each chamber and man does it sound good. I love low bass so this worked perfectly and the bass is accurate,not muddy and no delays. I was skeptical at first but I'm telling you GET THIS!!!

Pros: It does what it says

Cons: None

A Must Have!!

Written By Vodo, NY on Sunday, October 05, 2014

Crutchfield Customer Review (What's this?)

Built a box knowing I was going to use Very limited space but put the Largest speaker I could with High hopes of this working and was NOT Disappointed!!!!!!!!!!! Made this small box SHAKE THE GROUND!!!!

Pros: No brainer.

Cons: None

enlcosure stuffing

Written By airussell1, Memphis TN on Saturday, August 09, 2014

Crutchfield Customer Review (What's this?)

This polyester fiber stuffing might be the quickest way to add volume to an enclosure without expanding its dimensions. Product works just as advertised.

Pros: Quick and easy enough, once you figure match the internal volume of your enclosure to the stuffing.

Cons: Could have used a reference to how much is .3 or .7 cubic ft i.e. of this product, and suggestions about optimal installation.

Awesome Stuffing!

Written By Drew M, Pataskala, OH on Monday, May 26, 2014

Crutchfield Customer Review (What's this?)

Fantastic product. Great quality polyfill. Came in a blanket type roll that was easy to lay down and trim to size. Much better than loose polyfill competitors. Thick and heavy product that help lower the tone of my subwoofer's driver.

Pros: Density. Blanket style design. Cost

Cons: Waiting for it to come in the mail

Improved Bass

Written By BlameTheBird, Destin, Florida on Friday, April 25, 2014

Crutchfield Customer Review (What's this?)

I built a box to hold two 10" sub speakers and to fit under the back seat of my 99 Dodge Ram 1500 extended cab. In order to make it fit under the seat, the two enclosures barely made the inimum 0.80 cubic feet of area that my speakers called for. I got two of these and it worked out, as one order fills 1.0 cubic feet pretty good. And the speakers sound great!

Pros: Maximizes the performance of small speaker enclosures.

stuffed my box

Written By Mike, Detroit, MI on Sunday, April 06, 2014

Crutchfield Customer Review (What's this?)

Got the stuff for good measure, put it in the new box, seemed to sound better than my old box that didnt have it. worth a shot, seems to work

good stuff

Written By joe, va on Friday, April 04, 2014

Crutchfield Customer Review (What's this?)

very simple to install,makes a sealed box great.

Does what it says

Written By Anonymous, Iowa on Friday, March 14, 2014

Crutchfield Customer Review (What's this?)

Does what it says. Good value. More provided than I needed

Pros: Does what it intends to do

Cons: None

Polyester Fiber Stuffing

Written By Anonymous, Akron, OHIO on Tuesday, March 11, 2014

Crutchfield Customer Review (What's this?)

Fast shipping, good price.

Pros: Fast shipping, good price.

A Must Have

Written By Joe Joe, houston tx on Monday, March 03, 2014

Crutchfield Customer Review (What's this?)

Made my sub hit a lot deeper its a must have for any sealed box

Pros: All thumbs up

Cons: none

Polyester Fiber Stuffing

Written By Anonymous, Montpelier ohio on Tuesday, January 21, 2014

Crutchfield Customer Review (What's this?)

Wrks great made my sub sound deeper

Great Product

Written By Kim K., Houston on Monday, December 23, 2013

Crutchfield Customer Review (What's this?)

I added this stuff to my down firing sub box outfitted with a 10" Kicker CompRT. Without the stuffing the bass was hitting, but was not as deep as I wanted. I added about .4lbs because my box is .4 cubic ft. Now the bass is a little deeper and or faster songs with a lot of double bass it is much cleaner and less over lapping of the bass drum. Overall for the price I think it is well worth it in smaller boxes to get more ass out of it.

Pros: Easy to use. Cheap.

Polyester Fiber Stuffing

Written By J-dawg, DC on Wednesday, July 24, 2013

Crutchfield Customer Review (What's this?)

polyfill works like it should; keep things nice and tight-

Pros: fluffs and settles nicely

Good value

Written By Chan, New Bern, NC on Monday, July 22, 2013

Crutchfield Customer Review (What's this?)

This poly fiber will work well if you are filling an small enclosure or if you want to line the inside walls of an enclosure.

Pros: Low price

Cons: The poly fiber is pretty flat and does not expand very well compare to fill an enclosure compare to some other brands of poly fiber.

Good stuffing

Written By Brenyn, Langdon, ND on Friday, June 14, 2013

Crutchfield Customer Review (What's this?)

This is a great way to make your subs think the box is bigger than it is. They fill up the box with easy and produce a great sound.

Pros: Great sound, easy to install

Cons: It's hard to vacuum up off of carpet!

This is a Must for all sub boxes

Written By DJB, San Diego on Tuesday, June 11, 2013

Crutchfield Customer Review (What's this?)

If you want your sub box to sound the best. You need to put this in it!! It is worth every penny you spend on it.

Cons: None

Works great for Sub boxes

Written By Rick A, New Berlin, NY on Thursday, May 09, 2013

Crutchfield Customer Review (What's this?)

Purchased this a while ago and have used it on several Sub boxes. Used box building software and it told me how thick to apply in the sub boxes. Just use adhesive to glue inside the box. It can help to trick the subwoofer into thinking the box has more internal volume. Worked great with a pair of Infinity subs and with a pair of JL subs. I would definitely buy again when I need to build more boxes.

Pros: Low Price, fair amount of stuffing, Helps to minimize box size

Polyester Fiber Stuffing

Written By Anonymous, Indianapolis on Wednesday, May 01, 2013

Crutchfield Customer Review (What's this?)

I'm sure this product works well, but I never used it as the box I purchased already had poly fill in it.

Great on rap songs

Written By C-dub6, Yuba City, CA on Saturday, October 13, 2012

Crutchfield Customer Review (What's this?)

Right now I have a 15" kicker comp vr getting 500 watts rms to it and a little over a 2 cubic ft box. I got 2 orders of this and put it in and I gotta say, it definitely works. Just like everyone else is saying it makes it produce a lower sound, makes your car rattle more, and let's you crank more power to your sub without distorting. I found it works great for rap songs. Cuz with a 15", it's always hit the lows well, but the higher frequency rap songs my sub sounded like it didn't want to play them as well. Now with the stuffing it plays those better too. The downfall to this stuff, with my set up at least, is that songs that don't have a lot of bass to begin with get more deadened. Like some rock and classic rock. I have to crank up my bass twice as high to achieve the same sound I had to begin with.

Pros: Substantially increases your bass for rap/hip hop. Good price. Easy to install.

Cons: Kind of deadens the bass on songs that had little bass to begin with like some rock and classic rock. It's like these songs benefit more from the air volume in the box you sacrifice, rather than the stuffing. But it seems you can turn your bass boost up to twice you normally use to and acheice the same sound you had

If you really need it...

Written By PhilSam, Bartlett, IL on Sunday, August 05, 2012

Crutchfield Customer Review (What's this?)

this price is not what they should charge for this, unfortunetly they do. I have a custom box with 1.332 cu. ft inside vol. with a 300rms MTX 10" subwoofer. I have one or two tracks I usually play to push subs when we get new stuff to see what they are made of. Speaker before stuffing sounded really good, super bassy, and had a strong push you can feel. I ordered a pound (16oz) bag and not enough for recommended volumn. I wanted to see what the material was made of. Soft pillow stuffing is all that it is. I bought a 10oz bag of coarse stuffing and had plenty now. I stuffed the box and I have to say, the same songs, same bass and settings had more of a (bare with me) clean "Bhmmm" and less "Bhaah" sound. I'm lucky to have had the opportunity to try both ways and I am a strong believer that sealed boxes with the right set up can't be beat. This has been a hobby of mine since I could drive a car. Stuff your sealed boxes to solidify your tones.

Pros: Residual sound dampening and muffling. Stuff your box if your not satisfied with your sub. Still not happy? Buy a new sub but, keep it stuffed.

Cons: More is not always better!!! If you pack stuffing in the enclosure too much where it starts to become dense, you are LOSING volumn and Defeating your purpose. My woofer and I cannot tell the difference. Do your homework 1st. I only gave it a 3 because of the price. 5 stars if it were more reasonably priced.


Written By ralph, phx,az on Saturday, June 09, 2012

Crutchfield Customer Review (What's this?)

stuffing works fine would be better to get the right box instead of having to use the stuffing

Cleans up distortioN

Written By TobeMac, Bronx, NY on Wednesday, April 11, 2012

Crutchfield Customer Review (What's this?)

I gave this product 4 stars, becasue I used it in a ported box and I also think it's a little on the expesive side for what it is. If I would have used it in a sealed box I'm sure I would have given it 5, despite the price. This stuff does exactly what it says it does. I am able to send more power to my 8" Alpine type R ( in a Sound Ordnance ported box), and not experience the distortion that I had before. The sound is cleaner, more accurate and slightly deeper. The difference is noticable, but not drastic. I recommend this product.

Pros: sound is cleaner, more accurate and slightly deeper

Cons: pricey for what it is

Solid Hits.

Written By RickW, San Diego, Ca on Saturday, February 04, 2012

Crutchfield Customer Review (What's this?)

I got 900 watts going to a Polk 10". It hits

Pros: Good for small boxes

Cons: Should be $2.

So little does so much!!

Written By Kennedy, Columbia, SC on Thursday, April 28, 2011

I have 2 JL's in tightly sealed box with only .7 ft^3 space, so I thought this would do
little to improve my sound. Man was I wrong!! I added a 1lb. to each woofer and I
can't believe how much tighter and accurate my subs sound now. Not to mention it
really makes it easier when setting up your front stage. WHY DIDN'T I GET THIS 5

great upgrade at a great price

Written By Zey, Boca Raton, FL on Thursday, October 21, 2010

Crutchfield Customer Review (What's this?)

After replacing my entire Bose premium (?) sound system on my 350Z I started
having a lot of distortion especially from the sub I mounted behind the driver
seat. I started my distortion killing project by spending 2 days on covering the
doors and all around the sub box with Dynamat. I got pretty good results, but I
was not satisfied. Then I started checking the specs for the sub and sub box and
figured my sub box is a little smaller than it is supposed to be comparing the
specs of the sub. I decided to get a bigger custom sub box for my sub and
installed it behind the seat. Again, I had an improvement but there was still
distortion coming out of the sub. I was pretty frustrated after spending about
$300 and days for Dynamat and sub box replacement and I started checking for my
options and I decided to give this polyester stuffing a try. My sub box is about
.7 cubic ft. so I put 1 pound of this stuff in the box and turned the system on.
The result is UNBELIEVABLE!!! Distortion was completely gone and I was able turn
the volume on a lot more than I did before with no distortion from the sub at
all. Don't get me wrong, not only this stuff but everything I did on the system
helped to have a nice system. But this stuff made the biggest difference for me.

Works Great to Fill Body Voids Behind Car Speakers

Written By no7up, Spokane WA on Sunday, May 02, 2010

Crutchfield Customer Review (What's this?)

I have used this stuff before in sealed subs with great results. So when I needed to take out the hollow-sounding boom in my rear speakers, this stuff really fit the bill. My rear speakers (Dodge Dakota) are mounting in huge empty body spaces, and you could here a terrible booming sound at the resonent frequency of the cavity. I stuffed the cavity with fiberglass insulation in the lower part (they are huge spaces) and topped them off with this stuffing. The result was outstanding! The big boom is gone and all I have is tight clean bass. Now when I add the sub (sealed box on rear seat), it will not have to compete with the big boom - all that's left will be clean bass from 40 Hz to 200 Hz. Highly recommended!

Stuff you box

Written By Mike, Tampa, FL on Wednesday, March 03, 2010

Crutchfield Customer Review (What's this?)

I purchased this stuffing with my 2 subs and my box. I can surely tell you that the bass is
a lot clearer and also hits harder than not having it.

I would recommend this stuff to everyonee who wants that added clarity to their subs!!!!

Polyester Fiber Stuffing

Written By Jaime, Lake Havasu City, AZ on Monday, May 04, 2009

Crutchfield Customer Review (What's this?)

This makes bass really nice and crisp. Would recommend anyone to buy

BIG improvement!

Written By Grimzreaper, somerset, ky on Wednesday, January 14, 2009

i have a sony 10in xplod truck box. when i first hooked it up, it sounded
fairly decent, accurate, and handled my hard rck music well. i decided to put
some filler in it...stuffed it FULL (the filler was coming out of the speaker
cutout! lol) hooked it back up, and the sound was louder, very tight and
accurate, and it doesnt distort as much if at all. i HIGHLY recomend this stuff
to anyone with a sealed box looking for less distortion, higher volume, and
deeper, tighter bass.

This Stuff Actually Works

Written By Aaron, Bozeman, MT on Wednesday, August 27, 2008

Crutchfield Customer Review (What's this?)

I was extremely skeptical when I ordered this stuffing. I went ahead and did it because it was cheap and the two 10's under the back seat of my chevy truck just didn't sound very good. I had previously had the same two subs and the same amp hooked up in my car in a type 2 trunk box and they were awesome, but in the truck they just weren't very loud and seemed to distort way to easily. I ordered two pounds of this stuffing and it surprised me how big it was when it came in. As I started to stuff my box with it, I thought "man, this is rediculous! There's barely enough room in this box for all this stuffing." But I stuffed it all in because my box is two cubic feet and a pound per cubic foot is recomended. I put the subs back in, and man what a difference! I can turn my system up twice as loud as before with no distortion and much deeper, fuller sounding bass. In addition to being able to up the volume, I was able to turn up the gain considerably on my sub amp. This is the cheapest and one of the best improvements I've ever made to my system.

Polyester Fiber Stuffing- And some testing.

Written By MidnightCE, California. on Sunday, May 06, 2007

Using polyester fiber stuffing to 'fool' a subwoofer has long been a widely held belief, that honestly, doesn't really make a lot of sense.

I took an 8" subwoofer, and mounted it in a well designed, but slightly too small, enclosure. Inside, I placed the appropriate amount of polyester fiber stuffing.

I used a real time analyzer at 12db/oct resolution. (Most are only 3d/octave, this is a very revealing device.)

And, I played pink noise from 20-100hz. Pink noise is when every octave of sound has the same energy.

I did an A/B test, using this test equipment with and without polyester fiber stuffing.

The result?

When polyester fiber stuffing is added, a small amount of low end response and overall volume is lost. The same result as robbing the enclosure of airspace.

The exact opposite of what it is supposed to do!

Polyfill does have its uses - In a completely square box it can break up standing waves.

Polyester Fiber Stuffing

Written By gameguru1360, Temple City, Ca on Wednesday, February 14, 2007

Polyester Fiber Stuffing is an old trick used to trick a sub into thinking that the box is larger than it is. I would recommend adding polyester fiber stuffing to sealed boxes although some ported boxes benefit from adding it. For sealed boxes, using the roll or weave polyester fiber stuffing is recommended. For ported boxes, using the rolled polyester fiber stuffing is recommended as the weave will break apart and escape through the port.

Recommended amount is 1lb of polyester fiber stuffing for every cubic feet

One of the components I used in my system

Written By B-rad, Akron, Ohio on Friday, July 21, 2006

Crutchfield Customer Review (What's this?)

Once I had my enclosures finished, Type #1 sealed box, one JBL GTO 8" sub per box, .35 cubic foot inside dimension, 200 watts RMS per sub, I put the Polyester Fiber Stuffing in one. I read a review on the website that said the it made a huge difference between a box with and without it, so I had to check it. I took both boxes, (one with polyester fiber stuffing and one without), and hooked the subs up to the amp. in my other vehicle since I had the boxes done before I had my amp. wired up in my Jeep. I hooked up the box filled with polyester fiber stuffing first and cranked it up. The sound produced was a tight, kick in the chest pound. I pulled the wires from it and hooked up the one without the polyester fiber stuffing. The sound wasn't as loud and it was muddy. The sub was vibrating and working WAY too much for what I was getting out of it. The polyester fiber stuffing made a HUGE difference in the sound quality of the sub. If I could give this a rating higher than 5 I would. It made that much of a difference.

Can you feel me,....can you feel me NOW??

Written By Javi, Arlington, TX on Wednesday, February 15, 2006

Recently I purchased about 2 lbs to stuff in a 2 cubic foot total, 2 chamber downfire box that was pre-fabricated to fit in my 2000 Dodge Ram. After a side-by-side comparison of two trucks with my (2)Infinity 10" 1030w's & my neighbor's (2)Infinity 12" 1230W's, there is a BIG difference! With the same exact voltage running to our amps, same voltage cd players, same caps, and everything MINE is significantly louder and deeper. Not only does the bass hit harder because of this Polyester Fiber Stuffing, but you can turn the volume up even more without it distorting.
WITHOUT the Polyester Fiber Stuffing the sound from the subwoofer seems to resonate throughout the box and create a hollow effect.
WITH the Polyester Fiber Stuffing the sound from the subwoofer is more precise and more air is able to be pushed through the subwoofer cone, thus able to generate more bass.
Overall, this is a great product & I would recommend this to everyone with a small or truck box.

Polyester Fiber Stuffing Fantastic

Written By opsldo, Virginia Beach, VA on Wednesday, September 14, 2005

Crutchfield Customer Review (What's this?)

I bought two pounds for a custom built 52 inch box holding two Kicker Comp 8 icnh subs. I noticed a much smoother and harder hitting bass after I stuffed the two separate chambers. I would recommend this for any custom built box. I think it definitely absorbs the sound waves and my two 8s' now sound better than the two 10's previously had in my truck!

Great for small boxes!

Written By Raymond, Baltimore, MD on Tuesday, May 24, 2005

I originally purchased 2 lbs of this to fill a box that I built that had over 2 cubic feet of volume. Well I didn't hear much of a difference. Then I Took the Polyester Fiber Stuffing out of my box and used it for my friends box that we had cut apart to make it smaller to fit in his camaro. When it was installed in that box....MAN What a BIG difference! It sounded like the subs were getting an extra 75 watts! Anytime you have a small box I suggest the use of Polyester Fiber Stuffing, especially truck boxes.

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What's in the box?

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  • 1 pound of Polyester fiber stuffing in box

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