A couple of questions about the Tempest driver...

Discussion in 'Archived Threads 2001-2004' started by Javier_Huerta, Jan 1, 2003.

  1. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hello!
    I just came back from my vacations, and I brought my Tempest and plate amps home! [​IMG]
    After realizing just how MASSIVE the thing is, I thought about testing the coils just for the sake of it. So I took out some other drivers I'm working with (Cerwin-Vega HED-12's) and began to test them in a free-air (with backwave cancellation, btw) environment.
    To my amazement, the Cerwins had more displacement than the Tempest! They could go down lower and hit a lot harder before bottoming out (this is a 12" driver, BTW). The Tempest, OTOH, exhibited the following trails:
    1) Bottomed out fairly quickly with one coil driven
    2) Made TERRIBLE noises when doing so
    3) Seemed not to produce a lot of volume at all
    So, obviously, I'm worried. I checked the driver, it seems OK. I double checked the connections, and all was fine.
    All I can think of is that Tempests either don't like being driven on a free air configuration, or that by driving only one coil I changed its Q so radically that its sensitivity went up a lot, and I was actually bottoming it out a lot.
    I'm worried. Is this normal? Will this situation change when I install the driver in the box?
    It would be very sad to see the Cerwins outperforming the Tempest [​IMG]
     
  2. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Jack, thanks for your answers!
    What I meant with testing the coils is that I wanted to see that the sub worked... nothing more.
    I mixed up terms, BTW. I meant the CV's seemed to have more Xmax than the Tempest. The spec sheet claimed 17 mm of Xmax, which I always thought was a bit of an exaggeration. After watching the cones move yesterday, I quickly noticed they indeed have huge amounts of travel with no bottoming out.
    The thing that bothers me is the noise the Tempest makes while performing this same test. It has a "scrapping" noise. If I change its orientation (horizontal, vertical, or rotate the driver on its own axis), the noise stops or is inaudible, and then if I move the driver again, the noise starts again.
    Another thing is, if I put my hand next to the wire mesh grille on the back of the magnet of the Tempest, a very strange noise comes out of it, as if something was loose inside of the magnet assembly.
    I guess I expected a bit more in the "looks" department of the sub (or in its build, it seems a bit amateurish to me). I'm comparing this sub to a pair of $60 ones, so I guess I have reason to be worried: The C-V's have no extraneous noises, don't bottom out as easily, and look pretty and well built. Obviously, looks don't count, it's the performance that does. All I'm hoping is that my Tempest isn't defective, because there won't be a way for me to return it to Adire [​IMG]
     
  3. Brian Bunge

    Brian Bunge Producer

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    Javier,
    Keep in mind the definition of Xmax, which is one way linear travel. Even if the CV has more mechanical excursion, Xmech, it's completely irrelevant.
     
  4. Allen Ross

    Allen Ross Supporting Actor

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    when i tested my tempest in free air, i also noticed the same things you are mentioning except for the sound coming from the back grill. all i felt there was air moving.
     
  5. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Thanks for your answer Brian! I keep learning more and more [​IMG]
    Allen, did you try putting your hand close to the back grill, or blocking it? The sound the sub makes is *very* weird, as if it had a couple of screws loose in there, or something...
    Other than that, I simply can't wait to have the EBS box built [​IMG]
     

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