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Building a cabinet

Discussion in 'Amps and Cabs [BG]' started by second chances, May 23, 2001.


  1. second chances

    second chances

    May 7, 2001
    buffalo
    I have a 15 inch speaker and i was wondering if anyone knew of a website that would show me how to build a cabinet for it. keep in mind i know nothing about building speaker cabinets
     
  2. sn0wblind

    sn0wblind

    Apr 20, 2000
    Ontario, Canada
    I think I saw an article on this very subject in a guitar or bass magazine, I also my be dreaming, but I'll look thru them this weekend and see if I saw what I saw, and let you know next week.
     
  3. forget building it yourself if your just trying to save some money, go to speakerhole.com they have incredibly cheap boxes that are great quality, I would not recommend buying one of there bass cabs with the speakers already in them, however since you already have a speaker you will be much better off getting it there, However if you want to build it yourself to be able to say "Hey I built that" then sorry man I can't help you.
     
  4. Your cabinet and bass speaker must be closely matched to each other. Also, building your own is a LOT of work... I roll all my own and can speak to this honestly.

    If you can buy a cabinet already made, you will save yourself a lot of work and grief.

    Grab a copy of my Musician's Reference spreadsheet from my site, as I have a lot of the speaker/cabinet data already worked out. I also have design programs and software signal generators available here.

    http://www.ofgb.org
     
  5. I tried it building my own and it wasn't pretty. I learned my lesson.

    You answer your own question when you say you know nothing about building speaker cabs. If that's a true statement, have one built or buy one ready made. It is a LOT of work and takes a lot of skill. Otherwise, you end up with an expensive pile of junk, and you still have to buy a cab. So I'm saying that in my experience, it is much better to design your own cab, then have a professional build it. Like these guys who built my custom 2-15 cab.

    http://www.armadilloampworks.com

    [​IMG]

    Chris
     
  6. nunk6

    nunk6

    Jul 29, 2000
    just curious but what would make building a cabinet so difficult? if it were ported then calculations would be more exacting-
    guess im not clear on how complicated a box with cones can really be
     
  7. Time: Hours. Days. Weeks.

    You need a truck to haul 4x8 sheets of material. A skill saw with an 8-foot metal straight edge will allow you cut with precision, albeit with difficulty. Jorgensen clamps are required to hold the straight edge and during the gluing process. Pipe clamps will also be required. A screw gun with a bucket full of deck screws is needed. A table saw is nice if you have one laying around (I do). A sabre saw or other zip gun for cutting round holes.

    Butt joints are simple to cut, but require precision cuts to fit accurately. If you have cabinet maker's skills you will know how. If not, you will be "learning on the job."

    You will need T-nuts, bolts, speaker hold down clamps, grilles, corner pieces, and carpet. Also mounting blocks for the cable jacks. If you are not biamping, you will need a crossover for the mid-bass driver. Or you can use a piezo tweeter as a (poor) substitute, which does not require a crossover. If you build a crossover, the parts come to $60 or more for a 4th order network. Bi-amping is easier.

    Once everything is built, you need to reinforce the cabinet with internal bracing. Once done, it is time to create the port. I suggest using standard PVC pipe, as it is cheap and plentiful. You can get up to 6" diameter PVC at any sprinkler supply place. Skip Home Depot, they don't carry the big stuff. Too small a port, and you get whistles and noise.

    There are internet sites to help you with design work.

    http://xsspl.tripod.com/Audio/Sound.htm

    This is my personal favorite. Read and understand everything on his site, and you will have most of down pat. This guy is very clear, and his calculators are dead on accurate. Pay special attention to his port calculators.

    Once you get an idea for your port, cut it long and start testing it. You can use the sound card on your computer, a digital volt meter, and any of the freebie software signal generators. I have a nice one on my site along with the PerfectBox design program:

    http://www.ofgb.org

    Rough test the port outside the box, then final test the length inside the box. This will change the tuning frequency. You can calculate the volume occupied by the port tube and subtract it from the cabinet volume, then check it against the internet port design calculator and get very close.

    Secure the port inside the box. If it is too long, you have to have a 90 degree angle bend. Keep the port no closer than 1 diameter to any wall inside the cabinet.

    Silicon RTV sealant is ok to use inside the box to seal leaks.. but... do NOT install your speakers for AT LEAST 24 HOURS cuz the fumes will EAT your speaker.

    Once done and working, you have to cover your masterpiece. I use Ozite, in the heavier of the two available materials. Get it from Penn Fabrication or TCH, both are on the web. $50 minimum order either vendor. Be sure to get all your corner pieces, wheels, handles, etc. Both vendors have very tasty paper catalogs and sell everything you can imagine for building your own. Very competitive pricing too.

    Now, ain't that easy?
     
  8. That's exactly what I'm talking about. That's why I payed to have it done.

    Chris
     
  9. Way to go, bgavin! That's how it is! I hate it when someone says, hey, that's a wooden box with some cones and tubes in it. I can do that! It's nothing personal, nunk6.

    I'm an experienced cab builder with an extensive array of hand tools, electrical tools and chemical agents, and an average cab takes me a week. And I don't even cut my own panels.
     
  10. Gabu

    Gabu

    Jan 2, 2001
    Lake Elsinore, CA
    Let me help to dispell another unfounded rumor... Building your own cab IS NOT cheaper than buying one.

    If you want a inexpensive cab. Get it from www.speakerhole.com .

    Good luck!

    BTW Thobbinut, that's a beaut of a combo there. :) Don't give me any ideas about mutating my 2x15 now... :D
     
  11. Same holds true for building your own amplifiers. It is NOT cheaper to build your own from scratch with all new components.

    As for the 2-15 combo, yeah it rocks .... like granite rocks. Heavy, baby. Good sound, though. Altec Lansing made a great 15 back in the day (model 421). Thanks for the compliment.

    Chris
     
  12. Oh yeah, and this is what happens when the inexperienced throw something together:

    [​IMG]

    OH the humanity! :eek:

    And that was one of my better jobs. :(

    It does sound cool, though. Looks like 400 hell, though.

    Chris
     
  13. BASS_PLAYERS

    BASS_PLAYERS

    Mar 3, 2001
    Ada, Ok
    I'm sure It's on it's way to being the next Ampeg SVT :)

    I tried to make one in woodshop one time.......I sold it to one of those guys that always have super sh!tty distorted bass sounds coming out of their vehicles. I made enought for a down payment on a custom cab off of that!!!!
     
  14. Amen to that my friend. I *do* cut my own panels, and it takes me a heckuva lot longer than a week. With my business, I have so little free time, and it gets multiplexed between family, friends, gigging, and building cabinets.

    Besides, the fun part is the engineering. Building the damn things is just plain work.
     
  15. Right on, brother. Design to your hearts content, then let someone else do the dirty work.

    That's what I always say. :D

    That's how my 2-15 was done. I did the paperwork, then let an expert do the woodwork:
    [​IMG]

    Chris
     
  16. Made me another... CAB!
     
  17. VERY nice. The routed recess for the driver is very tasty.

    I can't identify the driver in the photo.

    You and I need to chat further about RCF drivers. I have a large number of them in my reference spreadsheet, but have not yet run any of the numbers for response.

    What is your opinion of the RCF drivers compared to Eminence, JBL, and Electro-Voice drivers? I notice the efficiency numbers are pretty good, and I'm thinking these might be excellent bass drivers.
     
  18. It's an RCF L15L601. The thing weighs about 25 lbs! But what do you expect with a force factor of 21.7? I made pics of the 6" midrange (IMG StageLine SP-6/100PA) too, but they were out of focus.

    Last week I bought a router. Puts in a recess like that in 10 seconds! Cuts out the speaker hole in 30! Everything PER-FECT-LY round! Try that with an electric saw.

    Yeah we never got back on those RCFs. I'll try to email you a sheet with everything I got. It's very up-to-date. I'll remove my (kinda proprietary) design tables for my professional line of speakers, but leave the very useful cab simulation page in there.

    RCF seems to focus more on sound quality than efficiency, which Eminence seems to be obsessed with. Electro-Voice has (correct if I'm wrong) a rather limited list of bass drivers. JBL is absolutely fabulous. Overall a bit better than RCF. But it's hard to find JBLs at affordable prices in Holland. Not that RCF is cheap, but at least you don't pay 1/3 of the price for shipping (from Italy to Holland is only 600 miles). And RCFs are handmade, so I've read. And they have 30 or so bass / midbass drivers to choose from.

    Do you know Beyma? Their bass drivers have never been an option for me (extremely expensive), but they seem to last, and last, and last. For a high frequency horn I use a Beyma CP16. Beyma have all their specs online.

    J
     
  19. I see you and I think similarly as to bass design. The 6" mid-bass is the same concept I use. It cuts in around 200 Hz, and is good to about 6 KHz. I don't care about anything higher with a bass. All the acoustic power is concentrated below 160 Hz, so the 6" is not subjected to enormous power. Harmonics only.

    Router question: What are you using to cut your circular openings? I have a zip router that uses a center pin and jig arrangement. It is fine for 12" and smaller, but a bit too short for 15" openings. I had to resort to scribing the 15" opening then guiding the zip router by hand. Time consuming and less than perfect.

    I will have to run the RCF numbers to see how they work out. Yes, the JBL are fabulous, but they are awfully weak in the low bass from about 60 Hz and down. Again, I think the JBL are expressly designed to be efficient and loud, at the expense of low frequency extension. My favorite is the E-145 for bass work.

    I don't know anything about Beyma. Post the URL if you have it please.
     
  20. I plan to crossover at 600 Hz, and use the 6" strictly as midrange. The 15" will easily perform up to 600 Hz, after all it's not nearly a sub bass speaker. The reasons for such a high frequency crossover are 1. It's a passive crossover, and I don't like big inductors and 2. I want the 15" to cover the entire base frequency range of every note on my 6 string, so the 6" will be doing the harmonics and string twang only. In some other thread you said you may have to use 10s for your highs. I think, with a 200 Hz crossover range, you will have to.

    I have a vertical router with a base plate (I'm not familiar with the term "zip router"). I put in a 6 mm steel rod with a 90 degrees angled end to put through the center hole. It lets me do circles between 6 and 24". I have yet to make an adaptor for less than 6". I guess I have to make a movable 2nd base plate with a small center pin.

    BTW, try www.beyma.com simple as that. Just this afternoon I asked myself when the first Neodymium magnet equipped woofers would surface. The answer is Beyma. You should really check out the Nd series. They're not low frequency woofers, but their specs are very impressing.

    There's another issue I'd like to discuss. You are so focussed on flat response. I admit, my yellow-coned cabinets have (unmeasured) flat response between 30 and 20,000 Hz, but I have always wondered why I go through all this trouble to get this audiophile frequency response. Sure it sounds great and it's hard to explain exactly WHAT is sounds LIKE. We are two of very few to know. But why don't commercial bass guitar cabinet manufactorers pick this up? Or am I not looking hard enough (yeah I know Acme). Some time ago I put my bass guitar's output on a spectrum analyzer. About 20% of the signal is the root frequency of the note. Should we really increase our amps a factor 10 to get this 20% of those lowest, what is it, 5 notes? Is it all worth it? Because that new 15+6 cabinet I'm building will completely blow my other rig away in terms of loudness (sensitivity 101dB vs. 96dB, peak power 1400W vs. 400W), and will have only slightly less low end, and a lot more punch.