Ok, my Tempest project is about to begin, but I need to clear up some things...

Discussion in 'Archived Threads 2001-2004' started by Jonny K, Dec 22, 2002.

  1. Jonny K

    Jonny K Second Unit

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    I've got a Tempest Driver, an Adire AVA250 amp, and two 3" flared port kits.
    I'm going to be building the Adire Vented Alignment as shown here:
    http://www.adireaudio.com/Files/Vent...plications.PDF
    I'm going to be using MDF board for this. I plan on cutting the corners of the sides of the walls into "L" shapes, so they will fit together nicely (called dado grooves?). I will be using only wood glue.
    Now most of this is clear to me, but when it comes to attaching the amp and the driver to the box, that's where I need some clarification.
    The box is supposed to be completely sealed, correct? How do I attach the driver and amp so I accomplish this? I remember reading something about weather stripping. I have silicone at my disposal. All around the edges of the amp plate is a kind of squishy foam. The edges of the driver are just metal.
    I understand that putting a screw into MFD may chip the board. The amp and driver both seem to require screws or bolts to hold them in place. How do I go about this? And when explaining, please use lots of detail, as I'm not much of a wood working expert. I'm thinking about drilling a hole through the MDF where each screw hole is on the driver/amp, and then using a nut and bolt to attach it (so there is no actual screw going into the MDF, simply a bold holding from the other side). But I'm concerned that the holes I drill will be too close to the opening for the driver/amp, and the MDF will break when I drill them, or tighten the bolts.
    Is it a problem if I put the amp close to the driver? (stick the amp at the bottom on the side of the box, and the driver is on the bottom)
    As for the legs on the box, how should I make those? How should I attach them? These 4 little legs will be supporting about 150lbs if I understand correctly, so they will need to be very strong and sturdy (in case I want to move the sub, the legs can't snap as I pull it across the floor).
    Thank you very much.
    Jonny K. [​IMG]
     
  2. RayJK

    RayJK Stunt Coordinator

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    If you don't want to use screws straight into the MDF then "T" nuts would be the next choice. Many people use a double thickness of MDF for the front baffle so 1.25" drywall screws used to hold the speaker won't go all the way through. If you are careful the MDF won't break but you can pre-drill the hole if you want. Use a drill size half the diameter of the screw. For "T" nuts you'll have to drill a hole all the way through the size of the "T" nut opening. They come in a few different sizes, see www.partsexpress.com for the "T" nuts and get the corresponding size screws.
    To seal the speaker I use rope caulk that can be found in any home improvement store. Once you see it how to use it is self explanatory.
    Mounting the amp on the back baffle is the same only I'd use 3/4" screws to hold it or the "T" nuts.
     
  3. Aaron_Smith

    Aaron_Smith Stunt Coordinator

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    The MDF is not that likely to split if you're putting screws "through" it, from one surface to the other like you would if you were mounting a speaker or an amp. The splitting problem happens more when you're putting the screws into the "end grain" of the panel, like you would if you were using them to assemble your box corners.
    If you are going to make the box with rabbeted edges, I would make sure you measure very, very carefully as you're working or assembly may be a challenge. I'm assuming you have the right tool for a job- a good stacked dado blade for your table saw. If you don't, you may want to consider putting it together without the grooved edges.
    And even though it's much more expensive than MDF, consider using birch ply instead. MDF dust gets EVERYWHERE when you're cutting or routing, it's heavy, and generally very unpleasant to work with.
    Good luck!
     
  4. Kevin_Johnson

    Kevin_Johnson Auditioning

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    As far as the T-nuts go, I would have a layer of some other kind of wood on the inside of the baffle for them to "bite" into. OSB or something similar glued to the MDF would work fine. You may also want to use something like Liquid Nails to make sure the T-nuts are really stuck into the OSB.

    As to the legs, you could always put a base at the bottom of the legs. This would allow you to slide it around and can look real nice if done right.

    Kevin
     
  5. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    Another opinion on T nuts.

    When I built my tempest I have the t nuts bite directly into the MDF. They had no problem biting in and have not backed out.

    I have had both the driver and the amp of a couple of times, and never have they backed out.

    Using some plywood for the t nuts to bite into may add a little additional security from them backing out, but it is certainly not a necessity.
     
  6. PaulDF

    PaulDF Second Unit

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    Jonny K,

    I would definitely use T nuts to mount the driver to the baffle. Doubling up the baffle is good, and perhaps make the cutout on the inner baffle smaller than the outer, to give more space between the t-nut and the cutout edge. As for the legs, I used the round cutouts left over from the inner braces. Glue 5 or so together with a 3/8 * 6" stovebolt running through the center. I glued all the rounds together then tightened the nut 'til the glue dried, then sanded the edges a bit. Drill the appropriate holes in the bottom baffle (make sure you have enough room beside the ports.... Mine were not flared and were 4 inch ports, you might be okay), and use fairly big washers with a little caulk underneath. It worked great for me and are very sturdy. Look neat too! I have slid my sub around a lot, and even lifted by the legs!
     
  7. Jonny K

    Jonny K Second Unit

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    Ok, for these T Nuts:

    I first drill a hole through the board. I then place the nut so it fits in the hole and then hammer/screw it in so the prongs dig into the wood. I then use a bolt from the other side to to through the wood and screw into the T nut.

    Correct?


    Jonny K.
     
  8. RayJK

    RayJK Stunt Coordinator

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    Bolt might be a bit much, I use a flat head screw myself.
     
  9. Patrick Sun

    Patrick Sun Moderator
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    If you go to my DIY Projects link in my signature below, look for my SBS (my attempt at a box subwoofer design using a 1st generation SVS 12" driver). In this project, I mounted the plate amp to the side of the enclosure, and provide many photos of documentation of the process.
     
  10. Jonny K

    Jonny K Second Unit

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    Sweet.
    Jonny K. [​IMG]
     
  11. Jonny K

    Jonny K Second Unit

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    Hmmm...I wish all those pictures were all on one page so I don't have to keep clicking back and forth.
    Otherwise, great stuff. Thanks.
    Jonny K. [​IMG]
     
  12. Jonny K

    Jonny K Second Unit

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    Ok, now regarding how I'm going to seal around the driver...
    I have this double sided foam tape. It's kinda...foamy...and sticky (what else should I say?). Think that may work?
    Jonny K. [​IMG]
     
  13. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    If it is closed cell it will work fine.
     
  14. Patrick Sun

    Patrick Sun Moderator
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    Use single-sided foam tape if possible (in case you need to remove the driver in the near or far future).
     
  15. Jonny K

    Jonny K Second Unit

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    Ok, quick question. In regards to "64 ounces of polyfill", ounces refers to weight, or does it refer to density? I think weight, but my dad thinks density.


    Jonny K.
     
  16. Brett Loomis

    Brett Loomis Stunt Coordinator

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    Jonny K----- 64 oz. of polyfill is the amount in weight that the sub should be stuffed/filled with. For further conversions if this isn't clear. Let me simplify it.
    one quarter (1/4) pound hamburger weighs 4 oz.
    one pound = 16 oz. or 454 grams
    So going back to the old algebra days if you need 64 oz. of polyfill and we know that there are 16 oz. in a pound, then you will need X amount of pounds. Written numerically this is: 16x = 64
    Or in simpler terms 16 times what(X) = 64
    Or 64 divided by 16 =........4 POUNDS
    4 pounds of polyfill or 64 oz. will work just fine.
    If you have a triple beam balance or a electronic gram scale just use 454 grams per pound or 454 grams times 4 pounds for a total of 1,816 grams or 1.816 Kg.
    If you have either of these scales then I bet you have other interesting hobbies as well.
    I hope this helps.
    [​IMG]
     
  17. Brett Loomis

    Brett Loomis Stunt Coordinator

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    BTW, check out my pics of my Tempest. This sub is incredible and will blow you away if built tight and in the right enclosure.
     
  18. Jonny K

    Jonny K Second Unit

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    Well the project is progressing nicely. I've got the inner supports, 2 walls, and the top on the box complete. Tomorrow we finish the last two walls, drop the bottom on, and then paint it!
    It should be done in a couple more days. This is going to be so sweet.
    Jonny K. [​IMG]
     

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