Instructables

Add more bass to your speakerbox/subwoofer encloser on the cheap

Picture of 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

Picture of What you need
Go purchase, pillow stuffing from art supply, wal mart etc.

Step 2: 123

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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
aarchbold2 years ago
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 ?

thank you.. this will help me alot.. including the comments..
Spectrace5 years ago
why do you say "without buying polyfill"
pillow stuffing is polyfill
linuxlifer (author)  Spectrace5 years ago
No it acts like a buffer... it does the same but for the fraction of the price
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.
gzuckier richms3 years ago
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.
i just stuffed a pillow in mine.
any idea on the effects on different wattages? how many watts are you at, what size speaker?
linuxlifer (author)  taylorinalaska5 years ago
(removed by author or community request)
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.
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. =)
capkloud taiguy3 years ago
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.
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. http://www.arcavia.com/kyle/Equations/Stuffing.html 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 http://www.ajdesigner.com/fl_subwoofer/subwoofer.php
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.
defiant1 taiguy4 years ago
Took the words out of my mouth
JZ Price5 years ago
how tight should you pack it?
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. 
apr16945 years ago
what should be used to stuff it? cotton balls?
 You can use polyester pillow stuffing, which can be found in any craft store.
hoihoi1515 years ago
you could just buy a good sub to begin with.
DIY Dave5 years ago
Is that why people put stuffing in their drums? (to increase the bass)
effectively yes and no. the pillows in kick drums are to help guard against a punchy sound. if a drummer is performing onstage and they need pillows in their drum then the sound tech sucks. pillows in drums are for home use basically
DIY Dave5 years ago
should you stuff it full or just put a little bit in?