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Tempest Sealed Designs

Discussion in 'Home Theater Projects' started by KurtJ, Dec 12, 2004.

  1. KurtJ

    KurtJ Well-Known Member

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    Using LspCAD

    Model 230 l sealed design fr Adire, shows -3dB @ 37Hz.
    Model 230 l PR design fr Adire, shows -3 dB @ 22 Hz.
    Model 122 l sealed design fr Adire, shows -3dB @ 37 Hz.

    Is this correct?

    I want a low Q design even though I listen to both movies and music.

    Any thoughts? Am I doing something wrong with LspCAD?
     
  2. Scott Simonian

    Scott Simonian Well-Known Member

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    If you have the space I would go with the vented Adire alignment. It has the low Q sound of a sealed sub with the extention of a vented design. I have this sub right now and it is great for music and movies.
     
  3. AjayM

    AjayM Well-Known Member

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    In quite a few rooms a low Q sealed Tempest will get you flat responce into the low 20Hz range if not below that. You won't have that extra level of SPL capability, but if you are really pushing that hard than you probably should be looking at something more than a single Tempest anyway.

    To give an example I have a sealed Tempest in a 180'ish litre enclosure, and in my current room it's 3db down at about 22-23 Hz (not corner loaded in the middle of the screen), in the last place I lived I had a 3db down point of 17-18Hz, and had a mild bump in response at 20Hz (this was corner loaded stuck next to a huge wall unit), in another room it was 3db down right at 20Hz. The power of room gain helps out quite a bit, and can make EQ'ing the sub a bit easier (if you build a design to be flat to 20Hz in a software program you will have a rising response in your room).

    Andrew
     
  4. KurtJ

    KurtJ Well-Known Member

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    Looked at LspCAD, and noticed Qts, Qes are doubled what published specs are for the tempest. SPL is down about 10dB compared to WinISD with correct Qts and Qes entered. Any thoughts?

    Also, WinISD shows 314l box with Qtc= .577
     
  5. ThomasW

    ThomasW Well-Known Member

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    Yeap don't trust WinISD.

    Like Scott recommended, the Adire Alignment is a vented design with a low "Q". Sort of the best of both worlds.

    That's where I'd put my money
     
  6. KurtJ

    KurtJ Well-Known Member

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    Ok Guys,

    Santa gave me enough money for either a tempest sealed or Atlas 15 sealed subwoofer, Qtc=.707

    which one?

    Can this be moved to the New Co & Woofs thread?
     
  7. Robert_CA

    Robert_CA Well-Known Member

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    I'm in the process of geting the lowdown on the Atlas15 from Ascendant Audio. I already own a Tempest but I may be going to the Atlas instead and selling mine.
     
  8. KurtJ

    KurtJ Well-Known Member

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    I bought the Atlas 15 today along with a Rythmik 250 A from Kyle. Chad sent me an email with a few other specs: Cms = 388 mm/N, Rms = 2.873 N-S/M, BL = 11.96, No = .9585%.

    Also said that for sealed enclosure Q = .707 Vb = 3.7ft^3,
    Q= .5 Vb = 6.5ft^3. Also some interesting info on XBL^2.

    If you want a copy of it, email me and I will send it to you.

    kurtjamesma@netscape.net
     
  9. Robert_CA

    Robert_CA Well-Known Member

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    KurtJ,
    You've got a PM. Cheers!
    [​IMG]
     
  10. KurtJ

    KurtJ Well-Known Member

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    Sent.
    BTW, what type of enclosure do you have for the Tempest?
    How does it sound?
     
  11. Robert_CA

    Robert_CA Well-Known Member

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    It's a 214L ported Adrie alignment @ 15.4Hz tune. Lots of output, well balanced and efficient. Once I finished it, got it calibrated and broke it in, I spun up LOTR and AOTC dvd's at near reference - 'bout scared the livin' crap out of me on the ring drop and the ship flyby (measured 108+db on my SPL meter at 12'). Even playing the Tempest at more "sane" levels it blends fairly well with my mains. It' a good sub but it's big box and a heavy one (100+lbs). It you've got a large HT room, it will do very nicely for most purposes. The Tempest is a good driver. BTW, I'll be trying "I Robot" next.(Bought it for Christmas.)[​IMG]
     
  12. KurtJ

    KurtJ Well-Known Member

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    Cool.

    I posted Chad's reply to my email over on the New Co & Woof thread since some of that info isn't up on his website yet.
     
  13. Robert_CA

    Robert_CA Well-Known Member

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    Let me know how things turn out on your build. I am assuming that you plan to bulid the 3.6L sealed. Right?
     
  14. Robert_CA

    Robert_CA Well-Known Member

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    Oops! My bad! I meant to say 3.7 cu.ft.
     
  15. KurtJ

    KurtJ Well-Known Member

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    The driver and amp arrived last friday. I began building the enclosure the same day. Chad mentioned that 3.7ft^3 with stuffing, or just over 4 ft^3 without. I came up with a 4.12 ft^3 enclosure; sides measure about 22 inches.

    Anyway, if I need a smaller box after measuring SPL, that's ok. MDF is cheap.

    The box looked smaller on paper; holy cow!

    Made a few mistakes with the router requiring a few more trips to Home Depot for more MDF. Oh well, it's my first DIY.

    Filled holes and seams with filler and sanded. Filled again and will sand this afternoon. Then it's on to veneer over the MDF.

    I'm taking tomorrow off to finish the enclosure so as to have plenty of time this weekend for measuring SPL, moving around the sub, and listening. [​IMG]

    I've only been talking about building a sub for about 2 years now; my wife is happy because I won't be talking about it anymore.

    Yeah, right.

    If it doesn't sound quite right I might need to purchase a BFD, even build a second sub to even out the response.
    [​IMG] [​IMG]
     
  16. Robert_CA

    Robert_CA Well-Known Member

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    I'll be getting mine soon. Let me know what you measure in you room and also what your impressions are on the Atlas's sound quality.
     
  17. KurtJ

    KurtJ Well-Known Member

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    I finished the enclosure yesterday and put everything together. Sweet! Fired it up, and wow, what a sound. Just like it should be for a subwoofer: not really notice it when it's on, but notice more when it's not.

    Played it for a while today before calibrating it with the rest of my HT. Pod Race scene; too cool. Music; noticed a lot more of what I had been missing.

    Anyway, started setting levels with SPL meter. THX reference levels easy as pie. I blew a fuse on the rythmik 250, kinda scary the first day[​IMG]

    Fixed that and then I heard a buzzing sound coming from the Atlas 15. Not a good buzzing sound. Pulled out the Atlas and smoke was coming out of the enclosure! I thought, geez, what the heck did I do?

    Amp was fine, no electrical fire or burning wires. Hooked up the Atlas and watched it for a few minutes. I saw sparks from inside the motor structure below the spider. [​IMG]

    Got a flashlight. Looks like the voicecoil came loose or something. Lots of copper wire unwound.

    What's it all mean?

    I think I need to call Chad tomorrow. Send this driver back for another one.
     
  18. ThomasW

    ThomasW Well-Known Member

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    It means that the driver blew up .... [​IMG]

    Something was wired wrong, the amp dumped DC into the speaker, or the speaker itself was defective.
     
  19. KurtJ

    KurtJ Well-Known Member

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    I don't think it was wired incorrectly; I checked and double checked before I sealed everything up. And, it was working fine for a while yesterday and today.[​IMG]
     
  20. Chad Kuypers

    Chad Kuypers Well-Known Member

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    Well, you are the first guy to blow one up. [​IMG] I will have a new one sent out to you tomorrow.

    You didn't wire up the amplifier to the gold terminals did you? If you did, that is why it blew up. The silver terminals are for the 4 ohm voice coil which is twice as large as the smaller 2 ohm voice coil. You should also place a jumper across the smaller gold terminals.

    Did you have both terminals hooked up to the amplifier at the same time? I can run the Atlas 15 full bore at 4 ohms with MUCH higher power than 250 watts pushing it way past its excursion limits without a problem. You also mentioned blowing the fuse on the amplifier. I have a couple of guys running 500 watt plate amplifiers to them without a problem.

    No worries either way Kurt. [​IMG] I have a shipping label already printed out and placed on a new Atlas 15 for you. It will go out tomorrow. I'll give you a call so we can chat about what happened. Talk to you soon.


    Chad Kuypers
    Ascendant Audio
     

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