Beryllium tweeter ... Interesting stuff

Discussion in 'OT Technology' started by TenSteel, Dec 13, 2002.

  1. TenSteel

    TenSteel Ted Cruz suicide hotline OT Supporter

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    The new version of the JM Lab Grande Utopia, the Grande Utopia Be has been released. This time, they're using a Beryllium tweeter, of all things. Here's a link with specific info about the tweeter:

    http://www.focal.tm.fr/gb/home/utopiabe/tek/Tweeter.htm

    And here's the main page for the speaker specs:

    http://www.focal.tm.fr/gb/home/utopiabe/caract.htm

    Interesting technology, but it still seems a bit "behind the times" for a high-end company like JM Lab to still be using dome tweeters (even if they are inverted). IMO, they should be using ribbons for tweeters. I'm quite sure the moving mass of a ribbon is still far less than this newfangled Beryllium tweeter.

    Discuss.
     
  2. 04

    04 Guest

    Hmm, well I for one wouldnt call normal voice coiled drivers "behind the times". Its just a different way of converting electrical energy to mechanical energy....

    I don't see why the "inverted" part makes them so high tech though. I mean, its off axis dispersion characteristics would be less than a normal dome, althogh driver efficiency should be higher, so that is just another tradeoff IMO.

    I have only honestly heard one set of ribbions before, and yes, they sounded quite wonderfull, but they were electrostatics, is that what you are talking about?
     
  3. TenSteel

    TenSteel Ted Cruz suicide hotline OT Supporter

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    Ribbons aren't electrostatics-- maybe you're thinking of magnetic planar speakers? Ribbons are more similar to magnetic planar speakers, I think they're more or less just smaller versions of them. (Electrostaic speakers use a metal ribbon suspended in an electrical field.) I think the material they use for the ribbon itself is different compared to a ribbon tweeter.

    It sounds like you nailed the technical benefits of inverted domes, so there's no point in restating what u just said. :big grin: The most logical benefit I can come up with is that it makes it more like a "conventional" midwoofer by having the same shape. Sort of makes sense-- just because it's a smaller driver, why should it be shaped differently? :dunno:
     
    Last edited: Dec 14, 2002
  4. 04

    04 Guest

    Yeah, I am not really familiar with any of the ribbons or electrostatics, I am a voice coil man myself! :)

    Well, technicallly speaking, I could be wrong. I would guess that was the reason for making it inverted, but ya never know.

    I don't think they are trying to make it like the conventional midwoofer, the reason it is concave instead of the normal convex is that it will allow for more output if you are listening right on axis with the speakers. The more you move off axis, the more attenuation you get. But that would just be my guess.
     
  5. TenSteel

    TenSteel Ted Cruz suicide hotline OT Supporter

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    Well, if you wanna learn about planar magnetics, electrostatics, and ribbons, and the like, I'll give you a couple of links.

    http://www.howstuffworks.com/speaker5.htm

    Raven ribbon tweeter specsheet (pdf):
    http://www.orcadesign.com/Product pdf/ravendrivers pdf/R1
     
  6. TenSteel

    TenSteel Ted Cruz suicide hotline OT Supporter

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    Re: Re: Beryllium tweeter ... Interesting stuff

    I'm not sure what kind of crappy ribbons your Carvers use, but that seems extremely ineffecient for ribbons. I guess I'm just used to the high efficiency of Ravens. The Raven R1 has 95db senstivity, the R2 has 98db, and the kickass R3 has 100db (all are 2.83v/1 meter). I will agree with you that they are difficult to integrate with normal drivers. The R1 and R2 work well in MTM designs because of their high sensitivity. Even after you add an extra midwoofer though, you still typically have to detentuate it in the crossover by a few db. If you don't utilize the ribbon in an MTM design, the crossover will end up detentuating the ribbon much more.

    Other good examples of ribbons that are efficient:

    ATD LeRibbon (same one used in ProAc Futures) - 91db/w
    Philips RT8P - 92db/w
     
  7. 04

    04 Guest

    Re: Re: Re: Beryllium tweeter ... Interesting stuff

    Woah! Hold on. There is a big difference between efficiency and sensitivity! Efficiency is the driver output at a certain power input level, and sensitivity is the driver output at a certain input voltage. What is the nominal impedence of the Ravens? If its for instance 4ohms, that means it will be 3dB more sensitive than a speaker that is 8ohm nominal of the same efficiency.

    Also note the frequency response of the drivers. Typically when you make a driver try and cover a large frequency range, your sensitivity goes down, if you dont increase radiating area. Perhaps the Carver ribbions go quite low in frequency and do not have much radiating area?

    There are a lot of variables to consider.
     
  8. 04

    04 Guest

    Re: Re: Re: Re: Re: Beryllium tweeter ... Interesting stuff

    Yeah, if a ribbion went from 100hz to 30khz, it would have to be either very large, or be less sensitive. Just a different type of design.
     
  9. TenSteel

    TenSteel Ted Cruz suicide hotline OT Supporter

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    Re: Re: Re: Re: Beryllium tweeter ... Interesting stuff

    :rofl: I can't believe I read it like that. Gotta be finals insomnia.

    :slap: <--- me
     
  10. 04

    04 Guest

    Re: Re: Re: Re: Re: Beryllium tweeter ... Interesting stuff

    :rofl:

    To make it pleasureable its got to be sensitive! But it also must be efficient!
     

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