how to assemble a tempest enclosure

Discussion in 'Archived Threads 2001-2004' started by zane, Dec 14, 2002.

  1. zane

    zane Stunt Coordinator

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    i'm about to make the medium sized sealed tempest enclosure out of 3/4" MDF, I'm wondering if its better to make the joints with 90 degree cuts or wether it would be better to make the cuts at a 45 degree angle, also what kind of wood glue should I use, I was thinking about useing some kind of liquid nails wood glue, and last of all where's the stuff at walmart to stuff the box with and what do they call it
     
  2. Jeffrey Noel

    Jeffrey Noel Screenwriter

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    Zane, I've always used 90degree joints on my enclosures. They seem to work well for me and I don't really have the best equipment so I'm not going to try any 45degree joints.

    The liquid nails will work great. It holds very strong. Just be sure to use enough of it!

    The stuffing is called Polyfil and you can get it in, I think, 20oz. bags from the sewing/crafts department at Wal-mart. I think it's $1.97 but I've been known to be wrong.

    Also, don't forget to seal the enclosure from the inside using caulking. That will stop air leaks which can lead to bad noises!

    Best of luck!
     
  3. Dave Milne

    Dave Milne Supporting Actor

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    Zane,
    Jeffrey is right, butt joints (90 deg) are easier than miter joints (45 deg). They can be clamped in one dimension and tend to stay put. Miter joints require complex clamping fixtures to maintain alignment. I always use butt joints unless I'm working with pre-veneered plywood or MDF (where miters are necessary to eliminate "exposed" edges).

    I've never used liquid nails for enclosures... I suppose it would work, but it's awfully gooey and hard to spread, requires solvent to clean up, and has dangerously little set up time. Aliphatic (Titebond, Elmers Cabinetmaker's) or Urethane (Gorrilla) wood glues work very well --done right, the joints are stronger than the wood --and they're much easier to work with.
     
  4. Aaron_Smith

    Aaron_Smith Stunt Coordinator

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    I use regular old Elmer's wood glue...it's cheap, easy to work with, dries clear, easy cleanup, and gives joints that are stronger than the material itself. Anything else for speaker boxes is overkill in my opinion.
    I also broke down and bought the Kreg pocket hole jig this weekend... a bit pricey but I can tell it will be an enormous improvement in the way I make my speaker enclosures. It is SO easy to accurately align panels, and I can put a whole enclosure together in an afternoon instead of the clamp-n-wait process I used to use. I wish I would have bought this thing about 3 projects ago.
     
  5. Jonny K

    Jonny K Second Unit

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    Ok, I'm also about to build my first sub, a Tempest using the Adire plans...

    I'd just like to confirm. If I'm building this sub box out of MDF wood, it IS acceptable for me to use only wood glue on it, and not nails or screws, correct? It will hold ok?

    I plan on cutting some notches out of the board edges (dado grooves I believe) so they will fit together neatly, and it'll all be held with standard wood glue.


    Thanks.


    Jonny K.
     
  6. Ronnie Ferrell

    Ronnie Ferrell Second Unit

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  7. Andrew Pratt

    Andrew Pratt Producer

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    I've built all my subs and speakers with just wood glue and they're solid. I would recomend though that you double up the MDF to 1.5" thick for your speakers though...as well add some internal bracing.
     
  8. Jonny K

    Jonny K Second Unit

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    Well yes, I do plan on using clamps. And the designs provided by Adire all have internal supports. But what's this about 1.5" MDF? The plans call for 3/4", and that alone will make this box weight 150 lbs or so. Do I actually need MORE? Or are you just referring to the piece that actually holds the driver? (I'll be using the Adire Vented alignment, which has a bottom firing driver).
    http://www.adireaudio.com/Files/Vent...plications.PDF
    Jonny K.
     
  9. Andrew Pratt

    Andrew Pratt Producer

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    Jonny You can't over build a sub box so you have to either add lots of internal bracing and go with a thinner wall or double up the walls and use slightly less bracing inside...personally I find it easier to simply double the walls to 1.5" and use simple internal bracing but both methods work.
     
  10. Aaron_Smith

    Aaron_Smith Stunt Coordinator

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    FWIW, I made my entire enclosure (144l sealed tempest) with 3/4 mdf according to the adire plan, and everything worked well. As far as I can tell my cabinet is very sturdy and non-resonant. It is freakin' HEAVY even with 3/4 walls so I would think pretty hard about how far you have to move the thing before you decide to go any heavier.
    Personally, if it were me and I were going to go to extra effort to improve the enclosure, I would consider changing the box dimensions to the golden ratio, or make a non-rectangular box, before I'd double up on the walls. But rest assured... the plan as given works great!
     
  11. Jonny K

    Jonny K Second Unit

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    Good. The last thing I need to start worrying about is the golden ratio (one of the many things university taught me that I didn't learn).
    Jonny K. [​IMG]
     
  12. Andrew Pratt

    Andrew Pratt Producer

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  13. Aaron_Smith

    Aaron_Smith Stunt Coordinator

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    Good point Andrew. Just some food for thought- the box dimensions don't affect the fundamental bass frequencies, but each bass frequency has a harmonic series that could potentially be an issue (80 -> 160, 320 Hz and so on). If you play a 440 Hz "A" note on a guitar, you also hear the whole harmonic series above the A (albeit at diminishing levels). I really don't believe that any of this has too big of an effect on a subwoofer though as long as it's solidly built and properly damped.
     
  14. Dave Milne

    Dave Milne Supporting Actor

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    Aaron,
    Don't worry about the harmonics. That's what the crossover is for. The higher frequencies get sent to the other speakers.

    It's comical that the tweaks talk about "fast" bass. With a subwoofer, everything above 80 Hz or so is filtered out (within the limits of the filter slopes) so you don't need "fast".
     

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