Building a 2.1 system out of a 48"x96" sheet of 3/4" MDF

Discussion in 'Audio/Video & Home Theater' started by Howard, Nov 17, 2008.

  1. Howard

    Howard Lifer

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    I've created a AutoCAD 2000 .dwg file of the pieces that can be cut out of a 3/4" sheet of MDF to get 2x 0.375 ft^3 enclosures and 1x 2.9 ft^3 enclosure.

    http://www.lightningmp3.com/upload/plans_rev3.dwg <- many thanks to NL5 for hosting!

    Revision 4

    Notes:

    Outside dimensions for the satellites will be 8"x14"x9.5" (WHD). Outside dimensions for sub V1 will be 22"x22"x13.5" (WHD). Outside dimensions for sub V3 will be 22"x18"x15.5".

    The sub enclosure will fit up to an 18" driver, but the mounting depth must be less than about 10". Also, if you make it a ported box, you will need to fit the port yourself.

    As far as bracing goes, I've added some for both the satellites and the sub. However, you need to make sure that the specified bracing layout will not interfere with the driver motors or baskets (should be a simple task with a jigsaw, router, or rotary saw).

    As an aside, the driver cut-outs, dimensions and internal volume of the satellites happen to match those required by the Zaph Audio ZMV5...

    Disclaimer: I take no responsibility for totally screwing up your nice new sheet of MDF or for any other damages resulting from usage of this document. I have NOT tested this design yet. Do not operate power tools without adequate protection, etc.
     
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  3. Howard

    Howard Lifer

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    Some more info since nobody's taken the bait:

    The board can easily be sawn with the aid of a circular saw (yes) and a sawboard. Then grab a bunch of clamps, some wood glue, and have at it. If you're not experienced and/or do not have a jig to help set up the boards to be jointed, you may want to enlist the aid of a second person to help with gluing up.
     
  4. JDub02

    JDub02 Diamond Member

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    I've been tempted to make my own speaker cabinets. My problem is going to be the WAF of the cabinets I want to make. She's currently not happy with the small bookshelf speakers that I have now.
     
  5. Howard

    Howard Lifer

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    Go for in-walls?
     
  6. Howard

    Howard Lifer

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    Revision 2, with a squatter (squarer-profile) sub:

    http://www.sendspace.com/file/09w80h

    Sub outer dimensions will be 22"x18"x15.5". Internal volume will be about 2.74 ft^3 before bracing.
     
  7. Howard

    Howard Lifer

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  8. evident

    evident Lifer

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    I'm looking to do a pair of DIY speaker stands for my bookshelfs. ialso got another pair of bookshelf speakers that have blown woofers that i can probably get replacements for. good luck with your speaker cabinets!
     
  9. BassBomb

    BassBomb Diamond Member

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    What do you mean by "tested" in solidworks? acoustic tested?
     
  10. ivan2

    ivan2 Diamond Member

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    how do you know if the designs will work?
     
  11. Howard

    Howard Lifer

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    no i just fit the panels together
    the satellites have the same front baffle size and internal volume needed for the ZMV5

    the sub has been modeled in WinISD Pro with my driver
     
  12. Howard

    Howard Lifer

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    marble.jpg
    wood.jpg

    the bracing is windowed incorrectly in the second pic

    the braces should have full reinforcement along their edges
     
  13. Howard

    Howard Lifer

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    well, picked up my supplies

    i'll be cutting once i put together the sawboard
     
  14. heyheybooboo

    heyheybooboo Diamond Member

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    I hate to point out the obvious.

    Instead of gluing up a "guide ripper & sawboard base" and clamping it to your stock (with the saw riding on top of the apparatus) - why don't you just directly clamp your straight edge to the board to be cut with the shoe of the saw riding against the guide?

    MDF doesn't have 'grain' that may splinter from crosscut and the apparatus makes it very difficult to properly set your blade depth (which is more important in getting a clean cut anyway ...)
     
  15. Howard

    Howard Lifer

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    Because then you have to deal with the blade offset. Using a sawboard makes it foolproof.

    The guide does not affect blade depth in any way. You can still change the depth of the blade on the saw; it's completely independent of the guide.
     
  16. themisfit610

    themisfit610 Golden Member

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    I'm in process of building an enclosure for my car subwoofer.

    I'm a total newbie to any kind of woodwork, and today I managed to brutalize my way through cutting the hole for the sub with a jigsaw. Not great, but it fits without any problems.

    Now I need to get the sides screwed/glued together. I have appropriate screws, and I understand that MDF should be pre-drilled because it tends to crack otherwise. That all seems easy enough to me, but I'm not sure how I'm going to manage holding the pieces together for gluing / screwing. I did my sawing on the ground, with the piece of MDF raised on either side with a stack of scraps. Not exactly professional, I know.. :)

    So, how should I handle the screwing / gluing?

    ~MiSfit
     
  17. Howard

    Howard Lifer

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    Don't use screws at all.

    You need clamps to glue the wood together. Lots of them. Get a friend to help you position the boards (I don't think you have any jigs on hand).
     
  18. themisfit610

    themisfit610 Golden Member

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    I have two good sized clamps that can cinch down very tightly.

    Do you suggest doing one joint at a time, the whole thing at once, something in between?

    Thanks,

    ~MiSfit
     
  19. heyheybooboo

    heyheybooboo Diamond Member

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    Position the front of the shoe on top of the stock and align the blade with your cut mark taking the blade kerf into consideration.

    While holding the circular saw with one hand slide your rip guide against the side of the shoe with your other hand and hold the guide in place. Set the saw aside and clamp the guide in place. Transfer the measurement of the rip guide ---> edge of stock to the other end and clamp down. Double check each measurement.

    "Square the Blade"

    Extend the blade to its max depth and lock down. On your work bench flip the saw over setting it on its top. Retract the blade guard. Some saws have holes that align with the guard retracted through which you may slide a nail to hold it in place. If not, you can normally take a nail and wedge it between the guard and the housing to hold the guard in a retracted position.

    Place your square across the shoe perpendicular to the base - sliding it against the blade. Sight the blade along the perpendicular edge of the square and verify that the full length of the blade is parallel to the edge of the square.

    Typical blade depth when fully extended is around 2 3/8 inches (I've seen some Makitas go a little deeper). With the square against the 'bottom' of the blade at the shoe (closest to the drive shaft) your saw tooth at the edge of the blade should be against the square. If it is not (and most are not), loosen the miter knob and adjust the shoe to the blade accordingly. Once set partially rotate the blade (maybe 90-120 degrees a pop) and re-check for square. If you are 'happy' lock down the shoe.

    This verifies that your blade is perpendicular to the shoe and will give you a 'square' (90 degree) cut.


    "Setting Blade Depth"

    Place the circular saw on top of your stock (at the edge) with the blade guard retracted (with practice you will not have to lock it down though it may help initially as you perfect your technique). The blade of the saw should be against the perpendicular edge of your stock.

    While holding the saw in place loosen the depth knob and adjust the blade so that only a very slight portion of the saw tooth extends past the bottom of the stock. When you are 'happy' lock down the blade. The lesser the better - but if you 'cut it' too close (ha ha) you will not cut all the way through your stock.

    SAFETY FIRST! When making blade adjustments always unplug the saw.


    MDF is typically 'faced'. The surface material may be paper, melamine or a wooden veneer. Simply gluing an edge to face material without the use of any mechanical connection is a recipe for fail. At a minimum you should use glue blocks (held in place with braid nails if possible) along each glue joint.

     
  20. Howard

    Howard Lifer

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    work area
    slow progress
    closer view of jig

    My cuts so far have been pretty good. Not perfect, but I screwed up the sawboard construction.

    I have the sawboard guiding the foot on the foot's left side whereas I should have built it so that it guides on the right side of the foot. This is because the blade is about 1.5" from the left side and ~4.5" from the right side - putting more material under the foot obviously will reduce the tendency for the saw to tilt.

    EDIT: Please use spring clamps, or at the very least, one-handed bar clamps. The bar clamps I'm using are rather slow to set up.

    I can't say that I agree with this statement, but it does appear that you know much more about wood working than I do unless your post was copied and pasted.
     
  21. SphinxnihpS

    SphinxnihpS Diamond Member

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    Nice!

    Can you design me an infinite baffle sub that looks like a B&W snail?
     
  22. Howard

    Howard Lifer

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    Possibly, but you certainly won't be able to make it with a circular saw.
     
  23. SphinxnihpS

    SphinxnihpS Diamond Member

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    I have a jointer planer table saw band saw drill press and routers. I can make just about anything with those.
     
  24. NL5

    NL5 Diamond Member

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  25. Howard

    Howard Lifer

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    Revision 4

    http://www.sendspace.com/file/zs2mn1

    Easier construction for those of you with a decent table saw with extension or sliding miter saw.

    I removed brace 2 in the speakers because it interferes with easy crossover mounting.
     
  26. Howard

    Howard Lifer

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    I built the sub. Its panel dimensions are fine. Thing looks pretty ugly, so no pics.

    I'm using a ~120W plate amp and it's plenty loud for computer usage. Sealed it to the enclosure using some closed-cell weather-stripping foam tape.