Slashdot Mirror
Build Your Own Subwoofer
Gerard J. Pinzone writes "Here's a page that details the construction of a homebrew subwoofer." Another in a long line of "You can, but should you?" projects.
← Back to Stories (view on slashdot.org)
← Back to Stories (view on slashdot.org)
He only built the enclosure ... I was expecting a 50Mb AVI of the guy winding the coil and magnetising the magnets.
I just want to see how he hacked a router to do that.
Kidding...I'm not that much of a geek.
I would have loved to see him try to build one out of parts of a microwave, stove, dishwasher, and drying machine while using a fridge to house it.
See what happens when you have old episodes of MacGyver on tape?
/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i
This is some guys expierence making an ENCLOSURE. I got excited, wrapping a cone w/ wire, finding a good permenant magnet. NOPE - This is something that MANY MANY people have done. It is making a subwoofer that would be the challenge. Then again, making a proper enclosure isn't easy...
Next time get the title of the article right!
The DIY section on avsforum also has some info.
DIY subwoofers is another place to start.
In fact a google search yields about 16,000 results with the words "DIY" and "subwoofer".
Which brings me to...
Is this really news?
-S
--- What parts of "shall make no law", "shall not be infringed", and "shall not be violated" don't you understand?
its not that uncommon to build your own stereo equipment, people have been doing it for as long as there was stereos. In fact most car stereo junkies I know of build their own speaker boxes as it is much cheaper then paying someone else to do it and chances are will look better as it matches the look of your car. Had the guy made his own speaker I would be impressed
There is a strong and thriving community of DIY audio enthusiasts. I myself built my own tube preamp, interconnects, and power amp. Try http://www.speakerbuilding.com/ for information about building speakers. For broader information, go to http://www.stereophile.com and click on "Links 2 Die 4" (the l337-ness is theirs, not mine) and then on the DIY link.
Sure, it's great that the guy documented his project so others could replicate it, but it might be more useful if he mentioned how he calculated the optimal port length. Specs on resonance frequency, Vas, power handling, and other things might be nice as well. Or why he chose a ported sub rather than an isobaric or sealed design or something else. Not that there's a correct choice, but knowing a little bit about how and why he made his decisions might help others down the line.
This sig intentionally left justified.
People have been doing this for a long time (Building ENCLOSURES, not subwoofers). All those little bassheads that you see going down the street with civics shaking the windows out of your house do it themselves. It's simple and easy, and most companies that sell subwoofers provide very detailed and specific guides (more than that page) about port length for ported boxes, volume calculations, building materials, construction methods, and countless other things. And boy, MDF is a bitch to work with.. you need a carbide blade for the saws, and screws strip SO easily. Not to mention MDF dust is very carcinogenic (search around google) and smells bad. Expect this thing to stink up wherever you put it for a while. Most of the guides are in PDF format (For car audio) from the major sub manufacturers' sites: www.kicker.com www.rockfordfosgate.com etc Forque (Chester Bochan)
Building a sub is a great project. As a single driver speaker, it requires no crossover, and therefore is relatively easy to design/build. Plus, with some careful planning, you can get amazing results.
/.
I've built a couple Subs based around the Shiva Mk II driver this guy used, along with a 250W plate amplifier from partsexpress, and it is amazing. Easily produces useable bass down to 20 hz in a sealed enclosure (F3 of something like 17.3 hz in a 1.7 cu ft. box, if I remember correctly...). An adire sub kit easily rivals subs in the $1000-$1200 range.
Listening to one of these explains why audiophiles don't like those Sat/sub computer multimedia sets, and tend to call them a "bunch of crap". None of them produce any useable bass below 50-60 hz, and a lot of HT systems are designed such that the sub only STARTS playing from those frequencies down.
Having said that, I don't see why this is front page news on
This is where I get my recommended daily allowance of "Foot in Mouth."
That's nothing special is it?
You can buy your own plans for tubes or boxes all over the place.
A subwoofer is the actual speaker which he just popped into place right?
You can even download software to help you download dimensions:
subwoofer enclosure software
The man who trades freedom for security does not deserve nor will he ever receive either. - Benjamin Franklin
There's more to building quality speakers then just mounting drivers in a box: particularly with ported designs. Building a sub with controlled, tight bass is the challenge; anyone can build a deafening "rumble box".
-Chris
--an unbreakable toy is useful for breaking other toys--
given the low price for a system these days and the crap sound you'll get if you do it wrong, buy an iSub and a couple of sound stix at the Apple store and save yourself a couple of years of apologising for the crappy looking cabinets.
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
This isn't even a good explanation for how to create a subwoofer enclosure. It is completely missing any information on the critical variables that describe the attributes of the low frequency driver as well as the procedure for designing the enclosure and crossover network to work with the driver to produce an optimized system. You can't just throw any old speaker into a given enclosure and expect a decent result. If you don't design the enclosure around the Thiele-Small parameters for the driver you put in it you are basically throwing the driver into a pretty box and ignoring the most important factors...how the completed system will perform.
And I wouldn't be a good slashdotter if I didn't mention are several computer programs that help with the design of speaker systems. They are really helpful for designing a subwoofer. I used such a program to design the subwoofer in my car.
Just take a gander at the king of all subwoofers they made out of an old hard drive motor at MIT!
Software piracy is victimless theft.
... where are the Lego guys?
I own the 4th and 5th editions of this book, and it has everything you would ever want on enclosure design. You can pick it up from Crutchfield, or I'm sure Amazon, Barnes and Noble, etc. should carry it.
Overrated / Underrated : Moderation
They have no enclosure!
Regardless, why is this a big deal? I used to build boxes back in high school. They usually sounded awful but not always. Just had to get them sealed up and calculate the dimensions properly.
I had two JL 10W1's that sounded pretty good for a relatively cheap speaker.
The man who trades freedom for security does not deserve nor will he ever receive either. - Benjamin Franklin
One 26 inch home-brew subwoofer, coming right up!. They built it with the driver from an ancient hard drive. For those not up on Norse mythology, moljnir (several spellings seen) was the unstoppable hammer of the gods, carried by Thor himself. I'd say a building-shaking sub comes pretty close to that description. ;-)
News for Geeks in Austin, TX
This is an article on how to build a sub box, not the speaker itself. Many people build their own sub boxes, this is a pretty nice one from what I can see, but its not much different then whats in the trunks of many people across the world today..
There are many fine sites out there with information on building subwoofer enclosures. While the construction of this one was fairly robust and adequate, the design will likely have a very poor response. There are too many no-no's here to cover for a SlashDot comment. Y'all should try some real sites for a start:
I'm no acoustic engineer, but it seems you'd have to do some calculations to make sure the resonant cavity matches up to the speaker. I don't see any evidence that he's done any calculations whatsoever. How would you go about determining the optimal size and shape of the cabinet? Or does it not matter on such low freqs?
This has to be the worst Slashdot how-to ever. There is absolutely nothing geeky about doing it blind like this, especially considering how much information is available about doing it the right way. So kids, don't do this at home; do better!
What? Do you think this is for listening to MUSIC or something?
I agree about the how is this news part. Building enclosures is nothing new and by itself isn't terribly interesting. Now an article on how someone fit some obscene amount of subs into a tiny foreign car would have been much more interesting. I still remember running the numbers to see if we could fit 4 12inch subs in my friends nissan 240sx back when I was into that kind of stuff :)
Ooooh, for a moment when they said "Build your own subwoofer," I thought they meant out of spare parts at home.
Actually, he meant, out of parts taken from another subwoofer...
See what happens when you have old episodes of MacGyver on tape?
MacGyver could break out of a turkish prison with a straw and a toothpick...
I think I'll keep my JBL SB-5. I can deliver all those sounds that you can't hear but feel. :) A cool device with 4 speakers inside where they are facing eachother 2 by 2 in 3 chambers. PDF tech doc.
I have built subs for my car, but the only problems is that even when you get the sizes calculations right, it just doesn't always sound right. So this time I have settled with a pre-built one, the advantage here was the I tried a few in my car to find the one that sounded right in my car.
my sig
about 300 people out of my 1400 member highschool could have gotten alot out of this article..or rather the comments. they all seem to be of the mind that you can throw a pair of 15" subs in a plywood box and throw it in the back of your car, and then they wonder why it sounds like an amplified fart when the bass hits.
If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
In the 20 or so years that i've been listening to them, subs which use relatively small, high-excursion drivers in a sealed enclosure have been the best, especially for percussion. They need more power, but it's worth it.
Ported subs just don't seem to have the *punch*, and it's tiring to listen to music which has a lot of info near the resonant freq of the port.
I read at +3, so I might not have seen a link to this project. Have no idea if it is any good, but it's certainly cheaper than many other options.
(For those not wishing to slashdot OSDN, it's for gspeaker, a gpl software for determining speaker enclosure sizes)
Jesus was all right but his disciples were thick and ordinary. -John Lennon
nice looking enclosure. too bad that article has nothing to do with 'building a subwoofer'.
You're much better off scrapping the whole cone idea and go for a vane/cylinder design. They're much easier to build and often give much better results in a homebrew situation. Try here for some explaination: http://www.mindspring.com/~sdinc/pages/td_new_fam. html
matguy(.com)
I may be opening a social club in the not-so-near future. Among the various plans in getting the place up and running, one of the things I'm concerned about is the audio.
I could go the conventional route and just hang a bunch of Peaveys around the place, but I'm also considering using a big subwoofer under the stage and mid/high speakers on the walls and hung from the ceiling instead. I think this might give better audio quality as well as being easier to do -- not to mention safer, wouldn't want those big speakers falling down.
Does anyone have recommendations on such a setup? Are there any subwoofer speakers available that can handle a large space?
I hate to poo poo someone, but you poo poo'ed the guy's web site. If you use the Shiva driver he did, and build it like he did, YOU DON'T NEED NO STINKING VARIABLES OR CALCULATIONS!
;-(
Personally, I preferred the NHT, but "whatever floats yer boat", or, in my case, "whatever shakes yer gutters off the house". And yes, it really did.
I agree that this is hardly news, but it's not a bad little diy thing, either.
Mark
Note: I have no affiliation with Acoustic Visions other than a very satisfied customer.
BTW, I am now a nerd for hire. See here if you're looking -- would accept H1B transfer or TN1, preferably in the Dallas area or relo back to Canada.
You could've hired me.
Yes, and a lot (notice how it is two words) of people (including yourself) at your highschool appear to not know correct English.
If you are going to criticize written English, you better be a whole lot more careful. I took the liberty of using boldface to highlight your errors. "It" refers to a single thing and, thus, cannot be "two words." You should have said "notice how 'a lot' is two words". Note that the word "yourself" is boldfaced. The proper word to use there is "you." Would you say "yourself appear to not know correct English"?
While perhaps syntactically correct, "to not know correct English" is clumsy -- to say the least. You should have ended the sentence with something like "to be incapable of writing English correctly."
Ignoring your poor sentence construction and grammatical mistakes, you reasoning is flawed. You claim that "a lot" of people from his high school write poorly, yet you have only read his writing. You have no way to know how the other students write.
Still feeling cocky?
Your post has to be the worst Slashdot troll ever. Wait, I just did the same thing to you! The difference between you and me and the author of the article and slashdot is that the author and Slashdot have put up.
Me, one day I'll spend $60 for a cheap boomer that comes with it's own amp. I applaud the author for doing better.
DMCA, Hollings, Palladium. What might have sounded like paranoia is now common sense.
My first speaker was a smack horn. The effiency of a horn is much higher than a closed or ported speaker. I got 104 Db at 1 Watt at 1 meter when a normal speaker only makes about 90 Db. Since Decibel is not linear thats a very big difference. Need i to say that it was well worth the hassle? My old Marantz tuner could play the pants of off any mates systems even if it only had 100 Watt output because of the high efficiency of the speakers.
To build a complicated case is more expensive for a speaker manufacturer than to put in a speaker element that handles higher power. For your amplifier its better to have a nicer load.
HTTP/1.1 400
Now that you've built your own subwoofer, you can cover the higher audio range with a custom made plasma speaker!
"Leave the strategizing to those of us with planet-sized brains." -Tycho
It's not syntactically correct. "To not know" is a split infinitive. (Remember those?)
Actually, it is correct. In 1998, the influential New Oxford Dictionary of English admitted that "in standard English the principle of allowing split infinitives is broadly accepted as both normal and useful."
Anyone else get a mental picture of Michael J Fox turning up knob after knob, and standing in front of a giant speaker?
:)
*sigh* Maybe some DIY stuff should be left alone
He didn't build the speaker, he built the enclosure for it.
In any case, he used the Shiva II woofer, which I believe is only available without an enclosure, although there are some places making enclosures and selling them with Shiva's already in them. This woofer is around $100 if I remember right, and outperforms many premade commercial products by a longshot. If you know how to use a saw and some basic tools, this woofer is definitely the way to go. I think audioreview.com has some user comments on it, almost all of them positive.
Need Free Juniper/NetScreen Support? JuniperForum
Feh.
An interesting a do-it-yourself project, but can you talk with elephants using it, let alone load it into an Isuzu Trooper?
That seems to have been the going standard for servo-driven loudspeakers for a decade or two.
I had the unique experience of sitting rather directly beside a (somewhat lesser, but similar) dual-cone 15" unit for an evening as I played DJ. I'll spare the details, but do allow me to say that visiting The Throne after returning home that night after having everything homogenized (shaken, not stirred) by the subwoofers was uniquely euphoric experience.
[I'd include more prominent links to Intersonics/Servo-Drive, who still sells these monsters. But their web page is "currently down for reconstruction." Dumb shits. Their old page was at least informative, not to mention existant. groups.google.com for more information, I guess...]
Kid-proof tablet..
I used to have a 15" foldback wedge (those triangular speakers along the front of the stage) in the back of a Volvo 340. Lots of bass, without that subwoofer "whuff" that you always get. I hate that sound, where you get decent bass down to about 200Hz, then nothing, then a big peak about 40Hz. Instead of nice clean bass you get this "wumf wumf wumf" noise. It's shit, don't do it.
You can go to any neighborhood radio shack and get a book on doing all of your stereo building. A quick search through online book catalogues will reveal many books on the subject.
No, this guy's speakers aren't that great.
There are some good points, however. He's doing nothing of note constructionwise, but the larger choice of the sonotube has significant advantages and disadvantages. Big plus: tube shape means walls CANNOT flex from pressure. That allows for potentially thunderous reproduction of the sound coming out, without overhang or weakening of the fundamental. Big minus: the sound coming out is strongly colored by the inside of the enclosure being the second worst possible shape in the universe- worst is a sphere. Testing has shown that these shapes are the best possible for the outside of an enclosure, but the worst for the inside.
What I've found works best for really serious bass is multiple drivers of gradiated sizes. My mains are running 6.5/8/10/12 drivers series-parallel like a Marshall cab- wattage is comparable to four of the weakest speaker (6.5) series-parallel, because that's the one that'd blow first. I have a narrow but absurdly deep cabinet, internal walls, bottom two sections ported and the top two open-backed. I had acoustic foam in there but found that it sounded better in the mids to leave it totally open, since all the resonance and reverberation goes straight out the back. The bottom, with the 10 and 12, has two good-sized ports, but since the box is so big (and it's running acoustic suspension drivers, too) the port only extends the lows further- it is not tuned high enough to make 'one note bass', it's reinforcing the really extreme lows.
If you want a REAL geek audio project, make some supertweeters like I did. Small piezo drivers (I'm using some fairly rigid and tough-to-solder-to ones I got in bulk), mount them on something solid while leaving the middle free to flex (rigid mounting like superglue, not a soft gasket), and then take some envelopes with that clear cellophane stuff that crackles easily if you rumple it. Cut out rectangular pieces big enough that you can make an 'M'- you're going to be making a degradation of the Lineaum cylindrical driver. That requires a piece to translate piezo flex into true linear motion- as shown in the *spit* patent- this skips the bridge piece and applies flexing-disc vibration directly to the leaves of the driver. In doing so it fails to be a proper line source- but the weight of the moving mass is that much less!
Take two 'leaves' and superglue them together at the base. You can trim them a bit so there's a slight ) shape to the part that'll be glued to the piezo. Take a bit of acoustic foam, superglue the outside of the sandwich of cellophane on one side to it, attach it to the speaker to the side of the piezo (which you should have wired up already). Then do the same to the other side- you want a 'm', seen from the top, with the middle bit resting directly on the piezo. The 'm' shouldn't be too tall, but it does have to form full half-cylinders- it shouldn't be flat. Finally, if it's all good, put a dot of superglue on the middle of the piezo, and allow the center of the 'm' to be attached permanently.
How it works: pressure from the piezo displaces the cellophane. Since it's two loose semicylinders, it flexes, choosing to compress together at first rather than shift the whole structure outwards. Surprise! The semicylinders form an exponential horn- and you've just compressed the throat, forcing air out! In addition, the wave will travel outward from the center, until it dissipates by air resistance and eventually the acoustic foam mounting at the far end. This tweeter goes up forever, way beyond CD capabilities, very cleanly, and it also has phenomenal dispersion characteristics- very wide soundfield, virtually no beaming. The difference is not subtle.
In a perfect world, lots of people could work with this technique and develop it as free software is developed. I've seen the patents on the _refined_ version of this- involving a bridge piece between the (not truly linear) driver and the base of the cylinders- and until the patents expire, this is officially proprietary.
I am sure that will dissuade MANY slashdotters from getting cellophane, piezos and superglue, and building their own supertweeters. Don't you people know developing on ideas someone else had is wrong? Remember, whoever-it-was who said, "If I have failed to see farther, it is because I wasn't allowed to stand on anybody's shoulders, so there" ;)
Why have I taken so much effort to communicate this technique? Because I'm a speaker designer myself. I have numerous ideas that are in fact mine, and hybrids of those with things like the Linaeum cylindrical driver, some of which are just terrific. And I'm very annoyed by a reality in which I cannot function as a simple artisan and idea-haver, without patent-wrestling with corporations- and in which I can't even go ahead with my own stuff, as corporations will take anything that's really good, and patent it since I won't, possibly even stopping me from using something I've invented. It makes you want to hide and never build anything.
There's nothing to do but go ahead anyway, but understand that my 'outing' of a homebrew way to do a degraded form of the Lineaum piezo driver patent is a combination of 'power to the people' and simple bitterness. What would have happened if the person to make the first cone driver had locked it up with patents, filed extensions, retained control of it to the present day? There'd be virtually no speakers, is what.
I feel the ideas that MOST deserve patent protection are the ones that most harm the scientific environment through their being guarded by lawyers. 'swinging sideways on a swing' patents are harmless. The ones that are REALLY GOOD are the ones that NEED to disseminate out into society.
>Besides, your (legal, of course) MP3s and Quake III Arena will sound much better with one!
How well does it work with il-legal MP3's? Has anyone tested this??
I still remember running the numbers to see if we could fit 4 12inch subs in my friends nissan 240sx
Could, or should?
I saw a picture in car audio magazine one time of a honda accord (old style) that had somewhere around 30 18" woofers in the back.
He just had 4 or 5 big sheets of plywood with as many woofers as he could fit screwed in to it. no boxes, and the back of the car wasn't even sealed.
It must have sounded like complete crap, but it was possible to fit them.
Could, or should?
;-)
Could as in properly sealed with dividers between each speaker space (speaker boxes with no dividers is a big no-no), and that each 12 had the proper amount of air space. IIRC we went with 4 JL 12w5s because they would work well with 1.5 cubic feet of sealed enclosure air space. To help make sure the air space was sealed screws were placed every 2 inches to hold the box together with a bead of silicon between the joints and then another bead along the inside of the box at the seams. We managed to fit all of this monster into the back of the 240sx without losing the back seat.
Overall an enclosure of this type is not hard to build, but building it inside the hatchback of a car is a PITA. Lets not even get started on what it took to get amplified sound to each speaker...
On a side note, it surprises me that more geeks aren't into screwing around with car stereo. There is math, electronics, wiring, music, etc... all in one place. Sounds like something that would be right up many geeks alleys.
In woodworking a router is a device that is used to cut a channel or groove out of a solid block of wood. You can see some from Craftsman here, they are generally held with the cutting blade down, the cutting blade is in the center of the bottom of the device, and dragged around along your desired line or edge. Its use very similar to the triming of a large whole with a dremel, but designed to leave a better line than I can do with a dremel, there are hundreds of bits to leave various edges.
Degaussing scares the bad magnetism out of the monitor and fills it with good karma.