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Big room need big sub???

Discussion in 'Archived Threads 2001-2004' started by Garth, Aug 21, 2002.

  1. Garth

    Garth Auditioning

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    I’m new to the forum and new to sub building. I want to build a Tempest Based sonosub with the Bash 500s http://www.acoustic-visions.com/500S.htm . I’ve run a few numbers though the LspCad 5.22 and have come up with
    277l
    25% fill
    6”*22” port
    Tuned to 16.5
    .75” MDF plug .75” MDF cap
    Port and driver in bottom
    24” sonotub cut to 41.128”
    Could the experts of the forum please check these numbers and maybe let me know if there's anyway to improve it. I have a very large L shaped media room 1500sqft. The use is 50% movie, 25% sports, and 25% music. Is there a better design, more or less volume, higher or lower tuning that would be better for my usage.
    Thanks for all your input.
    Garth
     
  2. Jeremy Stockwell

    Jeremy Stockwell Supporting Actor

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    Garth,
    Sounds about right. You may have already, but if you haven't, you'll definitely want to check out Pat Sun's DIY Page.
    Your design sounds very similar to his Sunosub II.
    The only improvement that I'd suggest to your design is to add 1/4" plywood to your plugs (at least the bottom one) which will give you a full inch in the tube and will also give the T-nuts a better surface to "bite" in. Mr. Sun does better at explaining the advantages of this.
    I'm in process of a very similar design as well, so post updates so I can know how you're doing, etc. I'm probably a couple of months from construction yet, but I'll try to post updates too.
    JKS
     
  3. Dustin B

    Dustin B Producer

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    500W amp for a Tempest in an enclosure that size seems a little overkill to me. If the money isn't an issue go for it. Otherwise the AVA250 or PE 300-794 will provide more than enough power for that sub and cost you half as much or less.

    Your numbers look about right, but I'm not at my computer so I can't properly double check them for you.
     
  4. Garth

    Garth Auditioning

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    Yes I’ve looked at Pat’s SunosubII and I’m using it as a base. I’ve looked at Dustin’s and many others too. I’m just not sure how they come up with the volume above 214l and what works best in a large room. Dustin should I make the sub bigger? Has anyone used the Bash 500s in any sub yet? I’ve got the amp on order with the manufacture and the cost is not that much in Canada. Any and all help is needed.
    Thanks
    Garth
     
  5. Bryan Michael

    Bryan Michael Supporting Actor

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    y do you need t nuts cant you just use a corse screw and screw into the mdfb?
     
  6. Shawn Solar

    Shawn Solar Supporting Actor

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    T-nuts prevent the MDF from stripping. Most DIY'ers install and re-install a driver a couple of times and this ensures a tight seal when installing the driver. The best advise with T-nuts is to use that 1/4" ply on the bottom of the plug. Otherwise when you screw in the screws you chance stripping the T-nut from the wood and have to drill out the screw. It is more work in the beginning but is worth it.
     
  7. Dustin B

    Dustin B Producer

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    The volume isn't that critical from everything I've seen with vented enclosures. Within some limits and as long as you tune appropriately that is. Sealed on the other hand it's more critical. A particular volume results a particular system Q that will greatly affect the sound quality (but you still have some fairly forgiving ranges).

    There are rather large ranges across which you can build a sub. We just play with computer modelling software until we get a curve and size we like. If I could have fit the sub, I would have went to EBS (340L). But a lot of people really like the Adire Allignment as well. As long as you are 170L or more, up to about 340L (after that the driver starts to get underdamped, at least I think that is the term for the hump in the response you end up with around 20-30hz) and tune to 20hz or lower a Tempest will be happy. The problem with the smaller enclosures is fitting wide enough ports that still tune to 20hz or lower.
     
  8. Rudy H

    Rudy H Stunt Coordinator

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    You will likely have a very easy time bottoming out the Tempest in that massive of a box. I would probably stick with a 250 or 350watt amp just for the added safety.
     
  9. Mike Strassburg

    Mike Strassburg Second Unit

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    If you're looking for LOTS of bass in that big room consider a dual Tempest sonosub like I built. I'm powering mine with the HS500 from Adire and it's plenty.

    480L - which came out to 28" x 54 1/2" since the tube wasn't exactly 28" ID
    (2) 6" x 22" ports = around a 17Hz tune
    (3) 3/4" endcaps with 2 inside the tube
    stuffed with 8#'s of batting

    During testing I hit 127+ dB @ 31.5Hz

    If you've got a big room you should have no problem hiding it in a corner. This thing kicks major ass for movies, but also does a great job on concert DVD's & CD's.
     
  10. Garth

    Garth Auditioning

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    Mike you’ve got me thinking that a dual Tempest might be the answer. I’ve ordered the Bash 500s and can’t really send it back because I had to talk the guy into selling it to me. The specs say 375watts into 8 ohms, is this going to be enough power for the dual Tempest in the 480l sonotub tuned to 17Hz. Please all opinions welcome.
    Thanks
    Garth
     
  11. Garth

    Garth Auditioning

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    Well I got the Bash 500s, now I really need to know if this thing will work for dual Tempests or if I should stick with one? And if I go dual how do I wire them? This thing is a lot smaller and lighter than I thought it would be, no big heat sink, shipping weight was only 7.421lbs. Check the specs and let me know what you guys think? http://www.bashaudio.com/indigo_home.html
    Thanks
    Garth
     
  12. Kerry Hackney

    Kerry Hackney Stunt Coordinator

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    Garth, My home theater is in an area about 1100 sq/ft. One good thing is that large areas tend to be a little more even in response than a small room. The other thing to think about is that even though the room is big, people usually aren't listening to music or movies over on the far side. So, you really don't have to "fill" the whole room. A single tempest with 500 watts pushing it should do pretty well for at least the immediate listening area.
    I have to admit that I now use both my DIY Tempest and a Dharman. I am experimenting with seperate placements within the room but haven't reached a conclusion on what the "final" arrangment may be. I used them stacked for some time before trying them in seperate corners. I do think that there is potential for having them this way. You may want to consider two seperate subs over one big one. There are tradeoffs either way.[​IMG]
     
  13. Mike Strassburg

    Mike Strassburg Second Unit

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    Garth,

    Send a note to Dan W @ Adire to see what he says about the BASH amp pushing dual Tempests. Hard to get a better answer when you go directly to the source. He helped me with mine and I couldn't be happier.

    I'm sure it would work OK, and you could always upgrade to a bigger amp down the road if you want/need more power.
     
  14. Garth

    Garth Auditioning

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    I sent Dan an email and when he didn't get back to me in the first 5min, I called him. He said it would work great, not driving them to there max, I would have loud tight bass. So I ordered another Tempest to go with the one that's on the way. Any and all Links to dual Tempest would be great.
    Thanks
    Garth
     

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