Linkwitz Chip question?

Discussion in 'Archived Threads 2001-2004' started by Greg P, Oct 4, 2001.

  1. Greg P

    Greg P Stunt Coordinator

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    I read some info on the Linkwitz chip and understand what its doing without regards to the technical side. My question is a confirmation question. So the Linkwitz Chip will create or mimick a frequency responce in a box subwoofer of a lower Q. ( for example a box size with a sub of a Q of 1 can get a response of .707 with of course the drawback of eqing and excursion) However, the sound as far as distortion, GED, and how clean, tight and fast the sub will sound will still have the characteristic of a sub with a Q of 1? Could someone help explain this?
     
  2. Brian Bunge

    Brian Bunge Producer

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    Greg,
    I think you may be overthinking this a bit. The whole point of the Linkwitz Transform Circuit is to take a driver (or multiple drivers) with very large power handling and Xmax, stick them in a less than optimal sealed enclosure and "transform" the response to actually mimic the same driver(s) in a larger enclosure. The system's Qtc is what determines things like group delay and transient response. So in your example, you will have a subwoofer with all the characteristics of the same driver in a normal sealed enclosure with Qtc=.707. And of course, as you pointed out, the down side is the need for large Xmax and in many cases, one hell of an amp!
    Does this help?
    Brian
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  3. Dennis Kindig

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    Loganville?!?!?!
    Where's Loganville? [​IMG]
     
  4. Brian Bunge

    Brian Bunge Producer

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    "Where's Loganville?"
    Dennis,
    Actually, I live in Walnut Grove! But I have a Loganville address and a Covington phone #!
    We ought to get together with Patrick Sun and all the other folks in the Atlanta area sometime!
    Brian
    P.S. You do know that just past Loganville is Between?
     
  5. Jack Gilvey

    Jack Gilvey Producer

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    I would just add to Brian's post to say that not only can you *mimic* a driver's response in a larger enclosure, you can do much better. For example, a Blueprint 1803, regardless of enclosure, can never have an Fc lower than its free-air resonance (Fs) of 25Hz. Using the LT, you can pick anything you want, going much lower than would otherwise be possible.
    As far as a Linkwitz-transformed sub sounding "identical" to a sub that "naturally" has given characteristics, the only issue I can see is that of power input. Comparing the two subs, one will have greater (possibly much greater) power required to reach a given SPL. This could conceiveably lead to power compression issues, some non-linearities due to voice coil heating, and higher distortion. This is complete conjecture on my part, however, but it's why I think that, even when designing a box specifically for a LT system, it's best to go as large as possible, thereby reducing the gain required.
    btw, it's not a "chip" that you can order, it's a circuit that you build. There are circuit boards available, though, the component values for which are taken from the LT spreadsheet.
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