Bass gurus - Killer sealed box/plate amp sub design for my practically outdoor HT...?

Discussion in 'Archived Threads 2001-2004' started by Sanaka, Feb 26, 2002.

  1. Sanaka

    Sanaka Extra

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    The "ultimate sub design" thread going on with Mr. Wiggins of Adire is awesome, but a little too awe$ome for where I'm at[​IMG] . So the 'ultimate' killer subwoofer for me considers the following:
    Something in the range of a Parts Express or Adire plate amp - around 250watts - with a 12" or 15" driver - Shiva, Tempest, P.E. DVC - misc. hardware and some MDF is what I'd basically be budgeted at, especially since I may need a pair of subs (more later...)
    While I'm not running a real "audiophile" HT (yet), I HATE sloppy bass, and this system does a lot of music duty. This and the fact I've never built a sub before lead me to simpler sealed box design - I don't have my head around all the T/S correlations and less forgiving/complex/ported alignments.
    However, I'm a professional cabinetmaker. So ultra-trick boxes are not a problem. T-line design is thus very tantalizing, but nothing I've found in that realm seems nailed down or "tried and true" to the point I could plunk my cash down on it. If you know of something that is, I'm all ears [​IMG]
    My huge HT "room" could more aptly be called a pavillion - I'm in Hawaii and it's all open louvered walls and vaulted ceilings, totally open floor plan. Main listening area is 32' WIDE left to right, and about 19' DEEP screen to LazyBoy. This though is in the middle of a total connected space approx. 32'x44'.... practically outdoors, Zero room gain. So might a pair of subs be almost necessary?
    A pretty much humongous box (pair of boxes) is OK. I've got room [​IMG]
    I don't usually listen at 'reference' (just dang loud!)levels. I appreciate clarity at mellow volume over visceral gut blasting. So I don't need 116db at 16Hz. Something like around 100db, tight and pretty flat to about 25Hz would be fantastic.
    Am I dreaming the impossible dream? Your replies, ideas and recipies will be appreciated in the extreme by this overreaching newbie :b
     
  2. Travis G

    Travis G Stunt Coordinator

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    Sanaka,

    I would go with the Tempest. Ported boxes are not really much more complex than sealed ones although transient response will suffer a little. A well designed ported box will certianly not sound sloppy though.

    T-line designs are now not difficult to design either. Building is another story but since your a cabinet maker it should be a cake walk. A larger sized sealed box will a similar transient response to a TL. A medium sized sealed box will play almost as deep as a TL. For these reasons many feel that building a TL is not worth it. However a TL's subjective SQ is different than a sealed box. If you are interested in learning more about TLs, pick up a copy of the Sixth Edition of The Loudspeaker Design Cookbook by Vance Dickason. It will tell you everything you need to know.

    Trust me, you will still have room gain, just not as much as if you had an enclosed room. You are not dreaming; 100 dBs at 25 Hz is a piece of cake for the Tempest.

    Travis
     
  3. Sanaka

    Sanaka Extra

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    Thank you much for the reply Travis.

    Yah I guess i should finally break down and get the Dickason book - I'd love to see some thoroughly quantified process for a T-line. What is SQ?

    There's usually people scattered all over the floor in my listening area - would the ones farthest from a single Tempest be getting a 'thinned out' bass, i.e. is one enough, or would a pair be necessary for a 'full spread' of bass in my funky room?

    Anyone else with an angle on this?

    Thanks!
     
  4. Pete Mazz

    Pete Mazz Supporting Actor

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    That's a pretty big area for a single driver to fill. Tempest is a good choice for bang for the buck if size doesn't matter, but two would probably suit your room better. Of course with two, you might want more power to drive them. And so it gets back to budget.

    A single Tempest in an EBS alignment would give you what you're looking for. You "should" get 110+ dB max with a 250 watt plate amp.

    Pete
     
  5. Travis G

    Travis G Stunt Coordinator

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    SQ = sound quality

    I just meant that even though you can get almost as much extension with a medium sized sealed box and transient about the same as a large sealed box with a TL. They sound different than a sealed enclosure.

    I don't know if you will need two Tempests or not.

    Travis
     
  6. Sanaka

    Sanaka Extra

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    Thanks Travis and Pete.

    Something I just read says that SPL drops 6db for every doubling of distance from source. This seems like it could indeed make for funky differential across my large area, with some people easily getting half apparent volume (~-10db, i think?) as others.

    But since I'm not a SPL hound (That [email protected] I threw out is, I've been thinking, probably more than I need. Around [email protected] would probably be killer), how bout this: Two sealed Shivas, planted left and right under my mains?

    If this seems plausible, how much amp would I really need? Perhaps a PE 300-792 (120w) on each one?

    Also does my situation indicate a greater need/use for fully adjustable phase, versus 0-180 switchable?

    Thanks (anyone!) for your thoughts 8P
     

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