Professional Tempest Enclosure, (SWR)

Discussion in 'Archived Threads 2001-2004' started by Chris Tsutsui, May 12, 2002.

  1. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Preliminary pics of my sub have finally arrived. The sub isn't finished but it's in a playable state so I decided to share the pics:
    link
    SWR = The trapezoidal shape that stands for standing wave reduction. [​IMG] The shape is a frustum pyramid custum designed by yours truly built with the aid of a professional contractor at a workshop. Design is an alteration of the Adire Alignmet tempest tuned to 15.4HZ with 2 flared ports and Tempest 15" driver.
    Well this weekend I have been busy playing and tuning the sub and I just found some time to throw up some pics on a site. (under construction)
    The edges are virtually flawless with "pressure strong" lock mitered joints. The brace is assembled with longscrews, liquid nails, and transparent silicone caulk. The base and brace uses "special" screws in from the inside yet NO screws are visible on the outside except for the port/driver/terminal.
    The base has been edge taped with maple and the 4 side panels are also of maple. The top is solid brushed aluminum laminated MDF.
    The box will have a finish on it, after I spray the finish on it I will remove the plastic protective cover on the aluminum so it will shine. The maple legs are not attatched yet, the sub is just resting on them. The terminal is also barely in there.
    I've played it about 10 hours with movies and music and am impressed with the musical bass it produces. I still have yet to tune and work on placement. The sub shakes the floor yet the bass is very clean and accurate sounding. In DVD movies above reference level the bass carries theatrical force yet no rattles are heard.
    It took us three (3-5) hour days for the contractor to build TWO! of these subwoofer boxes. That's right we have sisters. One will be for sale and hopefully we'll get more than $150 to cover some of my costs. Calculations and concept designs took hours, I'll soon have a site explaining the whole process from formulas to the 50+ pics I have of the 2 of us building the sisters.
    To be continued...
     
  2. Kyle Richardson

    Kyle Richardson Screenwriter

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    Very nice Chris! I really like the look of the painted terminal and the inverse pyramid for the legs. Very nice looking!
     
  3. Richard Greene

    Richard Greene Stunt Coordinator

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    Your subwoofer is a beauty thanks to the unusual shape and nice wood. Makes my DIY tube Tempest sub look like ...

    a DIY sub.

    I don't want to spoil your post but the unusual shape should have no effect on bass sound quality ...

    you can predict the lowest frequency standing wave inside rooms or speaker enclosures by measuring the largest surface to surface distance which I'll guess to be three feet for your subwoofer:

    565/3ft=188Hz.

    So there can be no standing waves under 188Hz. in a subwoofer whose largest dimension is three feet.

    A subwoofer should have very little output at 188Hz.

    (I recommend subwoofer frequency response down at least 24dB at 150Hz. for a sonically invisible subwoofer).

    What this means is that standing waves are only a potential problem in very large enclosure subwoofers ... and if a subwoofer enclosure is fully stuffed with fiberglass or polyester, you NEVER have to worry about standing waves in ANY subwoofer enclosure. Also, standing waves develop between reflecting surfaces -- it does not matter if the walls are parallel, they just have to reflect sound.
     
  4. Jeffrey Noel

    Jeffrey Noel Screenwriter

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    Chris, while looking at other pics on your site, all I have to say is damn you are a fine artist. That "sketch" of your room with your dog on the couch is amazing. I wish I had your talent.

    BTW, that enclosure is gorgeous. Wow! Hope it sounds good!
     
  5. Bob Bartlett

    Bob Bartlett Stunt Coordinator

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    Really nice looking enclosure! The aluminum laminate on top, can you buy that in sheets and what is the approx cost?
     
  6. Patrick Sun

    Patrick Sun Moderator
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    Link to the dog sketch?
     
  7. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Thanks, yeah I forgot bass wavelengths are very long and the shape would probably have no effect, but the slanted walls might help reduce the standing waves in my room eh? There has to be some slight advantage to having a shape like it right? [​IMG]
    The aluminum top was actually a thin sheet of aluminum, (maybe 12 gauge?). We used a spray adhesive to press the aluminum on top of a 3/4" MDF sheet then used a table saw to cut the sheet at an angle to fit the top. The sheet we we used is a scrap we found in the shop so I don't know the actual cost.
    As for the tempest, it sounds great so far. There may have been a bit of work but the end result was rewarding to put smiles on my friend (the contractor) and my face. Next he said we could make a matching center channel stand and an AV rack. I havn't moved the sub away from the doorway since it's too heavy for me to move by myself. (Legs arn't attached). I'll move it around and work on tuning it next weekend with him.
    The bass is very clean and musical, I didn't feel air move around the room but could hear each undistorted note. The bass is easy on the ears while having theatrical impact during movies. I can't really AB compare it to anything but so far I'm pleased with the bang per buck I paid. ($440 for 2 enclosures plus parts to finish one)
    Kyle your tempest delivery came fast, I'll be sure to tell everyone that listens to my tempest where I got it from. [​IMG]
    This week I'll work on the DIY site.
     
  8. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Link with drawing on it
    Perhaps I should make a site with my drawings. I did that one in beginning drawing, the teacher said I went too dark on the couch.
     
  9. James W. Johnson

    James W. Johnson Screenwriter

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    By the looks of that drawing its clear your imagination is very well developed...this is a key ingredient to making

    nice DIY stuff like you have done.

    Good Job!
     

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