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cabinet building question

Discussion in 'Amps and Cabs [BG]' started by Crockettnj, Sep 24, 2005.


  1. Crockettnj

    Crockettnj

    Sep 2, 2005
    North NJ
    I am aware the MDF is very popular for bass cabs... i also konw that many use plywood.

    my question, for a 2-ish cubic foot cab for full range bass, is 3/4 plywookd requisite? can i get by with 5/8? 1/2? if i brace liberally?

    3/4 mdf weighs more than my prom date, so i would rather tweek it down a notch./

    real life experiences and suggestions and bracing advice appreciated.

    thanks
     
  2. parttimeluthier

    parttimeluthier

    May 7, 2005
    I just built a set of 2.7 cu ft ported cabinets for some 12" Celestion BX12 speakers I have. I did not want all the weight of 3/4 inch MDF or Ply as the Celestions have HUGE magnets on them and I had to trim weight where I could.
    What I did was build the top and sides out of 1/2" birch ply and the baffle and back (only) of 3/4 MDF. The 1/2" reduces alot of weight and by still using the full thickness MDF baffles it gives good support and damping to the speaker.
    I sprayed the inside of the cabinets with asphalt car undercoating as well as placing a layer of 1/2" upholsters foam to make sure the cabinet does not resonate. Remember to glue and screw. no nails please :rollno:
     
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I use 1/2 ply for everything, properly braced it's all you need.
     
  4. Bill... could you read the last 6-10 (starting with post 29) posts on the Mesa Walkabout Mega thread and weigh in on how the bottom passive radiator in the Scout cabs work... i.e., does any sound come out, etc.? The issue is placing the amp on a carpet vs. hard surface... thanks... sorry for the thread hi-jack.

    Ken
     
  5. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    SWR uses 5/8 in. thick plywood for the Goliath 4x10s... each side has a stiffener that runs front to back...Eden does the same thing.

    And as Bill indicated...he uses 1/2 in plywood.
     
  6. Crockettnj

    Crockettnj

    Sep 2, 2005
    North NJ
    You guys rock! thanks for the fast and informative replies.

    hey, wait, my thread was HIJACKED!!!!!!!!! lol

    in your spare time, i would live some picks of your fastening techniques and bracing techniques using 1/2 ply. DADO? RABBET? Pine 1/4round inside? cross braces?? shelf braces with liberal holes?

    trying ot get some ideas.

    LONG post below of my thoughts/ideas thus far... if you have time to see if i am on the right track:

    so far, i plan ongoing a 1.75 liter box (19 wide, 13 high, X deep) with 1/2 ply all around, 5/8 MDF front and back, and thinking about maybe a very holey 1/2 ply shelf brace running from left side to right (connecting the weaker side walls of 1/2 ply. holey 1/2 ought to weight nothing, i imagine.

    since 1/2 ply is sorta thin, i am leaning towards cove moulding or 1/4 round ( not sure, maybe 3/4" ?) on each inside seam. i will glue the cove (?) and screw to it from the outside through the 1/2" ply.

    SHould i go with 1x1 poplar strips instead of cove or 1/4 round? maybe it'd be stiffer and provide more material to screw into , especially the soundboard and rear? Maybe since the cab is small, 1/1 poplar side stiffeners , ala Eden, is sufficient?



    I was going to go with DADO routed into the sides bottom and top, and fit the sound board into it, but routing a 1/2" ply results in not so much wood left... maybe avoid this?

    It's my first box, and it is 75% as a PRACTICE. I like to tinker with projects an stuff, but i also want a product that is well done. most of the actual cutting will be done by a friend who is a part time cabinet (like, kitchen cabs) maker, with me hangin over his sholder/learning some pointers.

    HOWEVER, he knows NOTHING about speakers etc, so i have to provide ALL plans explicitly. (thats where i hope fellow TB'ers come in and show me pics and explain what to avoid.

    :)
     
  7. Crockettnj

    Crockettnj

    Sep 2, 2005
    North NJ
  8. whitedk57

    whitedk57

    May 5, 2005
    Franklin, NC
    I built a 212 cabinet using 3/4 inch plywood. It is solid.
     
  9. Joey J

    Joey J

    Jul 12, 2005
    If that's the case you don't want to wing it. If your building your own you either want a better cab than you can buy or you want to save money compared to a store bought cab or both. Building your own 1x12 or 2x10 or whatever traditional design you won't do either. A 1x12 is a 1x12 is a 1x12, you can use different grades of speakers but a sealed or ported box is just that. As for cost, you can't compete with someone like Dave at Avatar who has his boxes built for peanuts in China and pays 1/2 what you have to for his speakers. If your going to the trouble and expense to build your own go to a site that does plans for speakers that are better than same old same old. www.Speakerplans.com is one. Their plans are free, but there's not much more to them than some diagrams, so you need toknow what your doing. The best place I know of is Bill's site at www.billfitzmaurice.com. His plans aren't free but they include at least a dozen pages of text and pictures, he has his own forum to help you out, and the cost of the plans is less than the half sheet of plywood you'll probably waste doing it on your own. The speakers are better than anything you can buy for less than a grand, if that. No one sells cabs that can touch his DR horns.