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Build Your Own Subwoofer 232

Posted by michael
from the rock-the-house dept.
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.
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Build Your Own Subwoofer

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  • Case only. (Score:2, Interesting)

    by Anonymous Coward
    He only built the enclosure ... I was expecting a 50Mb AVI of the guy winding the coil and magnetising the magnets.
    • I too was dissapointed. I thought he would at LEAST mangle some existing sub to make it 40" or something crazy like that.
    • Re:Case only. (Score:4, Informative)

      by Syre (234917) on Saturday September 21, 2002 @09:30PM (#4305233)
      He didn't even build a good case, as far as can be told by that article. Maybe a good looking case, but if he didn't design the cabinet using simulation software, it's very unlikely that it's a good sounding case.

      In case you're thinking of a similar project, a good page with all kinds of information and links for designing and building your own subwoofers that actually sound good is here [scrounge.org].

      Here [wssh.net] is a page of freeware loudspeaker design software and links to more. And another such page of speaker design software is here [tripod.com].

    • Yeah, I mean big &£$%ing deal. "Wow, this man can use a saw and wood glue, he must be some kind of god." Yeah right...

      I made my own speakers at uni - total cost around £80 for a set of kick-ass 50W/side speakers (10" woofer). I used a freeware program to work out the speaker size and the port length to get them working. I've never been able to push them up to the limit, even outdoors! :-) At the same time, my friend built a sub-woofer, including making his own power amp for it with the roll-off frequency settable. At no point did either of us think we'd done anything special, worth publicising to the world as a major achievement.

      Grab.
  • Amazing! (Score:5, Funny)

    by dotgod (567913) on Saturday September 21, 2002 @08:03PM (#4305002)
    I used a router to cut all of the circles

    I just want to see how he hacked a router to do that.

    Kidding...I'm not that much of a geek.

    • Re:Amazing! (Score:2, Insightful)

      by superpeach (110218)
      Why, in England, is router said as root-er (the networky kind) and a router (the cutting kind) is said as, um, row-ter (where 'row' is the kind of thing you may have with your girlfriend/wife, not like the boat, which you row) - the way Americans say router (the networky kind). Who was it that came up with the idea to make written english so bloody (read: 'damn') confusing?
      • I wasnt aware of that, I prounounce both as root-er and I thought most people in the country did, perhaps it varies by region or something.
      • Re:Amazing! (Score:2, Informative)

        by Ed Avis (5917)
        I think one of them routes and the other one routs. But when you stick -er on the end the written difference disappears.

        There's a similar question with -ing, which has led some British publications to distinguish between 'routeing' and 'routing', but most people just write routing for both.
    • Re:Amazing! (Score:1, Redundant)

      by gmhowell (26755)
      You need to turn of the SG-1 and turn on New Yankee Workshop. This is a trivial task.

      Remove baseplate on router. Get plank a little longer than the radius of the hole you want to cut. Bolt to bottom of router using baseplate holes. Measure from center of router bit along plank. Drill hole through plank. Place this hole over center of hole you want to cut. Cut another hole, using plank as guide. Place bolt through plank and piece to be cut. Turn on router, swivel around bolt.

      Voila! You have cut a hole with a router.

      FWIW, I prefer the guy who uses the antique and archaic handtools over norm's "I have a $20,000 tool for just one job" manner. But Norm does have some neat tricks.

  • home made. (Score:5, Funny)

    by DarkHelmet (120004) <mark AT seventhcycle DOT net> on Saturday September 21, 2002 @08:04PM (#4305005) Homepage
    Ooooh, for a moment when they said "Build your own subwoofer," I thought they meant out of spare parts at home.

    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?

    • bah, MacGyver would have done it with 2 rubber bands in a pencil. I pity your lack of cunningness.
    • by Metallic Matty (579124) on Saturday September 21, 2002 @09:46PM (#4305285)
      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...
  • by YahoKa (577942)
    They are pretty simple to build and for $80 you can have a subwoofer that will make your whole body shake. I've seen it done.
  • How is this news? I like the article on how to do it, but I people have been building subs for a long long time. You can go to radioshack and buy everything you need to build a good sub. Optimus is not the greatest but Im sure you can get the encloserment and then go to a good speaker shop to buy a 12" sub speaker. Plus the 4 gage wire and blah blah blah.

    Oh well. Cool article!
    • 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 :)
      • 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.
      • 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.
  • Not a Subwoofer (Score:5, Insightful)

    by iamjim (313916) on Saturday September 21, 2002 @08:06PM (#4305016)
    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!
    • Re:Not a Subwoofer (Score:2, Insightful)

      by Mononoke (88668)
      I got excited, wrapping a cone w/ wire, finding a good permenant magnet.
      That's the driver. I believe he is talking about making a subwoofer, which would imply the use of the device at lower frequency ranges of human hearing.

      A driver, no matter what size it is, is not a subwoofer. Subwoofers can be made with a single 12" driver, with four 18" drivers, or even a 30" driver.

      No, he doesn't tell you how to make a driver.

    • A driver (typically a coil, cone, suspension, and magnet) is not a subwoofer. An enclosure (typically a pile of lumber, some screws or expensive clamps, a bunch of glue) is also not a subwoofer.

      Putting both of them together may make a "subwoofer", if things end up wired appropriately, but neither a box nor a driver is very useful by itself. It's like having a CPU without a motherboard or any other requisite component, and calling it a "computer".

      Next time, try to posess even a modest understanding of the topic before flaming the submitter/editor/whoever.

      Your mention that making a proper enclosure isn't easy is quite possibly the understatement of the century. The moving parts (drivers) of a completed loudspeaker assembly generally only account for ~10% of the final retail cost - and you're lucky if they spend even that much on it. The rest goes toward crossover parts (if needed), hardware like fancy gold-plated terminals, paying someone to solder it all together, and, mostly, a quality cabinet to put it all in.

      The cabinet is primarily responsible for making the speakers at your local high-end shop sound better than those sold by your friendly neighborhood appliance whore. It is big, expensive to build, and expensive to ship.

      The selection of design and materials is a very non-trivial exercise. Not surprisingly, the more difficult, time-consuming, and heavy designs tend to work better. More expensive materials (think Corian, granite, or good MDF, versus OSB) tend to sound better. Good engineering early on in the project can yield a shift toward zero for all of these variables, but everyone here knows that good engineering is similarly non-free.

      And speaking of engineering, it takes a lot of it to build a good driver from scratch. Common practise is geared more toward modifying an existing sample to do more of what you want, instead of building new. The variables are numerous, the parts non-obvious, and the mathematical predictions for what-does-what lacking. But if you really want to know about it, a good place to start might be back-issues of Voice Coil Magazine.
  • I was hoping this would talk a little more about the mechanical aspects of building the actual driver, instead of being mostly a guide to fitting a sub into a box. Or am I just missing something?
    • I was hoping this would talk a little more about the mechanical aspects of building the actual driver, instead of being mostly a guide to fitting a sub into a box. Or am I just missing something?
      Yes, you are missing something. A driver is not a subwoofer. I have 12" drivers in subwoofers. I have 15" drivers that are not in subwoofers.

      A subwoofer is a combination of driver and enclosure designed for greatest efficiency and flattest frequency response at frequencies from 80Hz on down.

  • Here's another guide [slashdot.org] for building your own subwoofer.
  • by sdo1 (213835) on Saturday September 21, 2002 @08:11PM (#4305026) Journal
    The DIY section on HTF [hometheaterforum.com] is filled with people doing DIY subs.

    The DIY section on avsforum [avsforum.com] also has some info.

    DIY subwoofers [diysubwoofers.org] is another place to start.

    In fact a google search [google.com] yields about 16,000 results with the words "DIY" and "subwoofer".

    Which brings me to...

    Is this really news?

    -S

    • nope, not news... how about something at least 5 years old? like making a tactile-transducer to strap to your lay-z-boy, make those quake/ut2k3 rockets really hit
      http://www.hometheaterhifi.com/volume_4_2/tac tile. html

      or my current fav design (for no particular reason, other than it looks cool), the passive reflex enclosure
      http://www.diysubwoofers.org/prd/
    • Kyle Richardson at Acoustic Visions makes custom subwoofers. He made one for me with which I am very satisfied: see here [acoustic-visions.com].

      Note: I have no affiliation with Acoustic Visions other than a very satisfied customer.

      BTW, I am now a nerd for hire. See here [hollan.org] if you're looking -- would accept H1B transfer or TN1, preferably in the Dallas area or relo back to Canada.

  • Subwoofers are one of the few things that home audio do-it-yourselfers can build that is at least somewhat cost-effective in terms of material, effort, and result (well, maybe planar ribbon loudspeakers, though the lines of magnets might be a bit of a pain). Put a nice, massive driver and bandpass filter into a well-dampened box of appropriate volume and spousal approval and you'll have something that not only adds to the depth of music, but will also give you a martini "shaken, not stirred" during your James Bond movie marathon. :)
  • 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.
  • Every 16 year old with a ride builds his own for his car. You know... boooommm boom boom boom boooommmm

    If they can, you can too. (And if you *can't*, please turn in your geek badge right now ;-))

    Besides, your (legal, of course) MP3s and Quake III Arena will sound much better with one!
    • >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??
  • Not too detailed... (Score:4, Informative)

    by cei (107343) on Saturday September 21, 2002 @08:18PM (#4305056) Homepage Journal
    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 [audiovideo101.com] sub rather than an isobaric [audiovideo101.com] or sealed [audiovideo101.com] 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.
    • 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.

    • What about real hornes?

      Sure they are a pain in the ass to calculate and not many is up to the task but built right it hurts to listen to them. The punch you get out of a quarts wave pipes (simplest horns) is pretty amazing.

      I think the reason hornes arent that popular is that they are hard to calculate and very difficult to build. Take the time and you have a speaker that blows most others away.
  • Score -1, clueless (Score:5, Informative)

    by Anonymous Coward on Saturday September 21, 2002 @08:21PM (#4305063)
    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 [kicker.com] www.rockfordfosgate.com [rockfordfosgate.com] etc Forque (Chester Bochan)
  • Yes!! You should!!! (Score:3, Informative)

    by Bobartig (61456) on Saturday September 21, 2002 @08:28PM (#4305082) Homepage
    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 /.
  • 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 [tripod.com]
    • A subwoofer is the actual speaker which he just popped into place right?
      Wrong. That's the driver. The 'Subwoofer' is the combination of driver and enclosure.

      A driver is nothing until you put it in an enclosure.

      • 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.
  • Good=Loud? (Score:2, Informative)

    by shoemakc (448730)
    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

    • In high school I messed around with this stuff. My metric on how good the bass was depended upon how much I itched my nose -- the vibration made my nose itch uncontrollably. The more itching, the better the bass.
  • 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.
    • You're a bit confused: the SoundStix are the two satellites plus the sub. The iSub itself it made to work in conjunction with the built-in speakers on the old, CRT iMacs, the built-in speakers on the eMac, and Apple's add-on, amplified speakers. The industrial design of the subs are the same, but the specs aren't.
  • What is missing (Score:5, Insightful)

    by divide overflow (599608) on Saturday September 21, 2002 @08:30PM (#4305090)

    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.
    • EXACTLY what I wanted to say. At least he did mention about messing up the port length. Myself being an old school autosound installer in my previous life I've designed MANY of these, somewhere on the order of losing count of just how many. Thiele-Smalls, the construction materials, to port or not to port based on the TS params of the driver, enclosure volume you have to work with and the volume of the vehicles cabin drasticaly affect how it will sound. You also have a lot of room to shape he overall sound, everything from those stupid-assed anoying boom-box systems we all so love *cough* down to a nice tight 'n clean system with the sub just fitting in with the rest of the musical range to cover. Sorry, getting kinda off topic here, just had to toss in my own $.02. Anyway, point is, you realy need to know what you're doing before before just tossing any old speaker in any old box. You may get lucky but most likely you'll be vey dissapointed if you do just try and toss it together without proper design.
    • by Lumpy (12016)
      that's because the subwoofer described in the site absolutely sucks... I ran the box plot on it... it is HORRIBLE with a capital H... sure it will sound OK if you jam 20 bajillion watts into it... but any nut can do that (note: 90% of the car stereos you hear are really crappy subwoofers with overpriced drivers and too much power.)

      The title of the article needs to be, how to build a homebrew low end subwoofer that will be the same as the $49.95 KLH units at best buy.

      Ick..
    • 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
  • Well, if you ain't that much of a DIY guy, you can buy such (not actually sonosub, but much sturdier) cylindrical subwoofers from SV subwoofers [svsubwoofers.com]. The latest PC+ series is already given praise over Home Theater across the web. And the CS Ultra series is... Well... Check for yourself [hometheaterhifi.com]! :)

    Oh, and they are an Internet sale only company - you buy subwoofers directly from them, there are no other dealers between you and them.

    And I don't own a SVS ... yet ^_^ (and neither do I work for them)

    • I own the 20-39 pci (its 39 inches tall and is tuned to 20hz). The best sub I've owned hands down, it uses little space, since its so tall, and is awesome for home theater, and it's very musical too, altho I tend to keep it turned down pretty low due to my taste in music.
      I can recommend one 200%.
  • nuttin special (Score:1, Insightful)

    by Skal Tura (595728)
    There isn't anything special on making a woofer by yourself, first i thought that the dude made the element by himself but naawh... You really don't need much skill to make a subwoofer, just some maths and a little skills to make the casing. If you have proper tools it shouldn't even take long for an experienced woofer builder. With experienced i mean knowing the little tips & tricks to avoid hazzle and problems. tho, that woofer probably sounds nice but there isn't anything special... i wonder where ./ is going with news like this, do they wanna do a news report when i assemble my next woofer? lol Or perhaps some of my other projects like liquid cooling to make cpu run at -15 to -10 celsius degrees, or perhaps mobo box sized server... NOTE TO MODDERS: I didn't want to troll but there simply isn't any idea to report stuff like this, there isn't anything special on making a subwoofer by yourself.
  • When i first read the title to this story, I said to myself, "Wow, some guy actually hacked together some magnets and other supplies and built his own subwoofer!" But it's just an enclosure!

    Wow, so what he built his own enclosure. This is common practice in both home and car audio and hardly worth the post on /.

    I build an enclosure for 2 subwoofers for my car when I was 16 years old. It's not hard, and there are many MANY pages just like this one out on the web.

    Another in a long line of "You can, but should you?" projects.
    Well if you can handle power tools, and a couple of simple caculations to get the right enclosure and port size for your subwoofer, then HELL YES! I still have mine in my car that are custom fit, and sounds better than the cheap enclosure i had before. I even used pvc pipe as the ports :P

  • Imagine a beowulf cluster of these!! hooo-yeah baby!! uh uh uh love that pussy!!
  • Ha! That's nothing! (Score:3, Informative)

    by Noose For A Neck (610324) on Saturday September 21, 2002 @08:45PM (#4305130)
    Just take a gander at the king of all subwoofers [mit.edu] they made out of an old hard drive motor at MIT!
    • Now that is building a subwoofer!!
    • Feh.

      An interesting a do-it-yourself project, but can you talk with elephants [google.com] 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 [intersonics.com], 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...]

  • by daTimster (588551) on Saturday September 21, 2002 @08:46PM (#4305132) Journal
    ... where are the Lego guys?
  • might as well get 15' of 10" PVC put a 10" woof appr.2/3 the way down(go get specs yourself) and get bass to stir your guts.

    • At a couple frequencies.

      That tube is only going to resonate at a few frequencies that are harmonics of each other. Yeah, you will hit one certain spot really really hard, but other frequencies will be attenuated.
      • well yeah,figure up the specs for something around 32hz and throw on bachs toccatta and fugue.bumpin the eq around the freq. you tuned the waveguide to kinda helps.(course most folk would be happy with somethin around 50hz,but hey make it go mooooo)
        i got another tuned woof plan that puts a 15" in the top of an openhead drum and tunes by filling drum with water till its where you want it.of course you could split hairs all day but this really is projects for experementation. if you want audiophile go spend the money.

  • moljnir! (Score:5, Interesting)

    by StandardDeviant (122674) on Saturday September 21, 2002 @08:58PM (#4305165) Homepage Journal
    One 26 inch home-brew subwoofer, coming right up! [mit.edu]. 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. ;-)
  • by zeno_2 (518291)
    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..
  • You call this news? Is SlashDot that hard up (or worse, flaccid) that this page worthy of being posted?

    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:

    1. teamROCS Technical [teamrocs.com]
    2. The World Famous Eddie Runner and Installer.com's Tech Pages [installer.com]
  • This is *BOOOOOMMMMM*cool cool, I think *BOOOOOMMMMM* i'm gonna try it *BOOOOOMMMMM* for my home *BOOOOOMMMMM* theatre!! The low end *BOOOOOMMMMM* would add a *BOOOOOMMMMM* lot to the experience *BOOOOOMMMMM* .

    J *BOOOOOMMMMM*

    *BOOOOOMMMMM*
  • by sakusha (441986) on Saturday September 21, 2002 @09:17PM (#4305210)
    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?
  • by Dr. Spork (142693) on Saturday September 21, 2002 @09:22PM (#4305214)
    This guy is obviously a pretty weak hardware hacker. I say "obviously" because if he knew what he were doing, his construction page would be covered with formulas about material desity, air volume, port circumferance, port length, and many other tuning-related issues. It look to me like this guy thought of a design that seemed right a priori, bought a driver, and started cutting. Pathetic!

    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!

    • by Erris (531066)
      ... thanks for all the destructive criticism. If you knew anything about "material desity, air volume, port circumferance, port length, and many other tuning-related issues." you should say so or point to a page you have that says so, right? If you read the article, you might have noticed how the author points to one of the many useful pages on how to do things "right".

      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.

      • I have no problem with people putting loudpeakers into anything. I mean, if you don't want to read up on the math and you have the cash to blow on trial and error, go nuts!

        My objection this: Of all the thousands of how-to pages available on the internet, why did this one make it to the front page of Slashdot? A subpoint was that if the guy had discussed his work from a "nerd" angle, it would have made a good /. piece. As it was, I thought it failed as slashdot material, and I still stand by this.

        I did indeed notice that the author points to a page where a more careful procedure is explained, and that just makes things worse. Why wasn't that page the subject of the /. article? Still better stuff is available, and I'm sure Google would help you find some of it, but that's not what I would do. When I was designing my speakers I actually (gasp) WENT TO THE LIBRARY! Do people still know how to use these? Anyway, I'd be shocked if there were stuff on the internet that comes close to the quality of what's published in peer-reviewed journals.

        In any case, I made my speakers the nerdy way, and that should be the /. way. I don't want this place to degenerate into "news for short-attention-span nerds." For example, if there are speaker how-to's posted, they shouldn't gloss over the very stuff that distinguishes a crappy speaker enclosure from an outstanding one.

  • 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 [jblproservice.com].

    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.
    • According to that spec sheet of yours, that subwoofer is terrible! I hope you didn't spend a whole lot of money on it, because about all it's good for is impressing people by telling them it has four drivers in it.

      Lowest frequency at 45Hz? Are you kidding? Any shoddy, thrown together homebuilt sub can handle at least 35, and ones like this guy has built can hit low 20's and high teens without a lot of effort.

      Regards,
      levine
  • by NeoSkandranon (515696) on Saturday September 21, 2002 @09:54PM (#4305302)
    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.
  • Acoustic suspension (Score:3, Interesting)

    by Alien Being (18488) on Saturday September 21, 2002 @09:56PM (#4305309)
    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 (Score:3, Informative)

    by gmhowell (26755) <gmhowell@gmail.com> on Saturday September 21, 2002 @10:15PM (#4305350) Homepage Journal
    I read at +3, so I might not have seen a link to this project [sourceforge.net]. 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)
  • The whole project is pointless without knowing what kind of frequency response this enclosure will supply. It will most likely be very loose bass looking at the basic setup (Not good for sound quality and not good for accuratly reproducing the sounds created by musical instruments). I would be supprised if the whole thing is really cost effective once you add up the price of the parts+time+block amp. Audio equipment is heavily marked up (Around 250%) But this is probably a hard area to beat the price/performance available in the store.
  • nice looking enclosure. too bad that article has nothing to do with 'building a subwoofer'.
  • Blue LEDs! Add some of those and you have a geek worthy article.
  • by matguy (7927) <.ten.noivilbo. .ta. .yugtam.> on Saturday September 21, 2002 @10:23PM (#4305374) Homepage
    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
  • 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?
  • 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.
  • Now that you've built your own subwoofer, you can cover the higher audio range with a custom made plasma speaker! [ihug.co.nz]
  • by Nate Fox (1271)
    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.
    • Your statement makes as much sense as the following:

      "He didn't build the computer, he built the case for it."

      A loudspeaker includes a number of components. A driver, such as the Shiva contraption, is one of them. A box is another.

      He assembled these components together. He built a speaker.

      Your next statement is similarly non-sensical. I'll convert it to an analog which you might understand:

      "...he used the BP-6 motherboard, which I believe is only available seperately, although there are some places building and selling computers with BP-6 motherboards already in them."

      Does this statement not disprove itself? Or is there some magic additive which must be included in a loudspeaker/white-box computer before it may be considered as a whole instead the sum of its parts?

      Is it a pre-requisite that such finished products carry an endorsement from Apple or Sony before they are recognizably complete systems? Or perhaps some other subtle nuance I've managed to miss in my many years of building complete systems myself?

      Please explain further. I fear that if you're correct, my speakers and my computers may suddenly disintegrate themselves into seperate parts.

  • 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.
  • Yes, you should build speakers. Building speakers is a terrific geek pastime.

    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.

    ....which only goes to show that I need to be using more of my paid-for web space to publicize the work that _I_ do, with no hope of recompense, ever, just to remain true to the principles I've set out. Other people do that- it's not unique to do so. It's merely taking sides, knowingly or unknowingly.

Mathematics deals exclusively with the relations of concepts to each other without consideration of their relation to experience. -- Albert Einstein

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