Add More Bass to Your Speakerbox/subwoofer Encloser on the Cheap




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If you ever wanted more bass to your sub woofer bandpass box? Now you can on the cheap instead of buying poly fill.

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Step 1: What You Need

Go purchase, pillow stuffing from art supply, wal mart etc.

Step 2: 123

1. disassemble screws, disconnect speaker wires

2. Stuff the stuffing into your box/sub woofer

3. re assemble wires, screws, face plate, speaker

Turn on your radio receiver in your system, and notice the difference in cleaner bass

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    25 Discussions


    2 years ago

    here's an article about "acoustuffing":


    Reply 2 years ago

    the general rule is to use 1 to 1.5 pounds per cubic foot of enclosure volume.

    i always thought pillow stuffing would be a cheaper alternative. you should see the prices some audio places charge for "blu-tak" which you can often get at dollar stores.

    i would have thought that "acousta-stuffing" would raise the Q of a speaker by limiting internal volume, but apparently, it has the opposite effect (provided you don't overstuff... it seems that 1 pound per cubic foot is better than 1.5 from what i've read) by making smaller (sealed especially) boxes "look" larger to your woofer by dampening back waves and lowering your f3 point.

    i've ordered a JBL GT5-15 for use in a 1.9 cubic foot box which actually is just short of the 2 cubic foot maximum recommended by JBL, but running the numbers, that produces a QTC of 1.15 where .707 is actually ideal. then when i ran the numbers for that QTC, i got an internal volume of 42 cubic feet! (about 4 feet by 4 feet square). on a graph, the bass definitely went deeper, but good luck buying an enclosure that big pre-fabbed.

    i'm going to try getting a couple pounds of pillow stuffing INSTEAD of using "egg crate" mattress liner as a poor man's acoustic foam to line the box with. pillow stuffing should not only be cheaper, but actually DEEPEN the bass and probably tame standing waves even better than mattress foam too and MAYBE even tighten the bass up by shrinking the air spring.

    so far, everything i'm reading says this is the way to go with a sealed box with a QTC over 1.0. thanks for verifying that acoustuff etc. is really rebranded pillow/teddybear stuffing.


    4 years ago

    Please does the size of sub-woofer box makes the difference of the production?
    And can i build two sub-woofer speaker in one box


    7 years ago on Introduction

    AARCHBOLD asks
    I think my subwoofer`s skeakers are too small. Can I just change them for two bigger ones without damaging the subwoofer ? What detail should I take into account before doing it ?


    7 years ago on Step 2

    thank you.. this will help me alot.. including the comments..


    Reply 10 years ago on Introduction

    No, it is the same stuff, just not at the inflated markups that audio shops charge. I found it cheaper to actually buy pre-stuffed pillows and gut them when they were on sale then even getting the pillow stuffing on its own.


    Reply 7 years ago on Introduction

    we used to use fiberglass, but you couldn't use the insulation grade stuff, you had to get special long fiber fiberglass so that the fibers wouldn't get into the speaker suspension and make it sound all scrapy. polyfill oughta be a lot easier to work with.


    Well, thank you for the umm... informative reply. I've seen this done in high quality home audio subwoofers and electronic keyboard speakers, and personally i can say that it improves audio quality dramatically, ported, sealed, or bandpassed.

    4 replies

    Reply 10 years ago on Introduction

    whoa whoa whoa. what polyfill does is impede the flow of air within the box, effectively tuning it so that the box appears bigger than it really is. if a box is already correctly built to the proper Q specs of a driver then adding more polyfill is actually detrimental to the sound. Fact of the matter is, space is often a higher priority than proper design so the box is shrunk in order to accomodate trunk space (or whatever else will be holding your sub). Air is very much an active part of the response equation.

    That aside, yes, polyfill is much less expensive when you get it from pillows. =)


    Reply 8 years ago on Introduction

    impeding the flow of air would lower the effective size of the box, not increase it. though your comment about proper building to the specs of the speaker, is correct.


    Reply 7 years ago on Introduction

    The air doesn't flow in the box if it's sealed, it just gets compressed and decompressed. Compressing heats it up slightly, decompressing cools it slightly; the effect of stuffing in the box is to absorb some of the heat, which as you might imagine is the same as having a bigger box; theoretically the effect is like having a 1.4X bigger empty box. The technical terms are adiabatic compression and isothermal compression. Again, that's sealed box, only.

    Now, if the box is ported, as they often are for greater efficiency, then the air does move in and out through the port, and we are talking a completely different thing. Typically, a cheap ported speaker has a big peak right at the bottom just above a very sharp cutoff, to get maximum efficiency and maximum low frequency. This accounts for the whump whump whump one- note-only sound of a cheap ported box. If you stuff the port with something, you do impede the movement of the air, and the more you plug it the closer it comes to a sealed box with no port, obviously. The comparison is, that a ported box theoretically goes down an octave lower but falls off twice as fast below that, compared to the same box with the port plugged. Cheaper ones tend to be designed with a big hump at the bottom to make it louder and bassier, but, as i said, without the ability to distinguish the various notes very well. More seriously designed speaker will be smoother down that end. In any event, the effect of plugging the port partially is, like you might expect, the more you plug it the more it tends to sound like a sealed box until it's completely plugged; which means, the dropoff starts an octave higher but is shallower, so there is still some response way down at the bottom, where the ported is down to nothing. The graph here is great
    Me, I've got a lot of those cheap speaker systems with subwoofers, like they sell for computers, etc, and I just stuff the port with old socks until I'm satisfied with the sound. I don't have any of them running unplugged; and although it's not serious home theater quality, even with their cheap little amplifiers, there's still enough oomph to do a good job on the TV movie effects, while at the same time music on tv shows is a lot more listenable.

    Usually you would pack it about one pound to every cubic foot.
    you can   play around with the amount of stuffing too.
    Adding stuffing to any subwoofer will slow down the air flow in side of the subwoofer resulting in am bigger box.