What do you think of this vented ACI DV12 sub (model output)

Discussion in 'Home Theater Projects' started by Tim Bargar, Jan 20, 2004.

  1. Tim Bargar

    Tim Bargar Agent

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    I like to get folk's input on what I've designed and how reliable the output might be. Maybe a few of you who have other design software could please input the driver data and see if the output is similar to what I've gotten from WinISD Pro.

    I am trying to design a cylinder sub with sub-20Hz extension (F3
     
  2. Tim Bargar

    Tim Bargar Agent

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    The Vas is off a sheet ACI faxed to me in 2001. So I assume it is correct. The Vas value I put in my prior thread was for a earlier DV12 model. The model I have is the newer model with different specs.

    I guess I don't understand the benefit of a flared port. I agree a 6-7' port seems ridiculous, but that is what WinISD returns. How should I go about determining port dimensions?
     
  3. ThomasW

    ThomasW Cinematographer

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    The only problem with speaker design software is that you need know how to design a speaker in order to use it......

    A single flared 4" port is plenty big for a DV12

    Here's a recommendation, use Unibox instead of WinISD........
     
  4. Arthur_King

    Arthur_King Stunt Coordinator

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    The only possible reason you could have for going up to a 6 or 8 or even 10" port is to keep port speed low. I guess that makes sense (full disclosure, im at work and havent run your Sub through WinISD or Unibox) but dayum, thats a lot of "port"

    If his airspeed gets very high with a 4" flared port, it may be "plenty big" but isnt he going to be hearing a lot of chuffing on high-LFE movies?

    Daffy Arthur King
     
  5. ThomasW

    ThomasW Cinematographer

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    Are people posting complaints about chuffing problems with moderate excursion 12" drivers and 4" flared ports?
     
  6. Tim Bargar

    Tim Bargar Agent

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    ??

    Arthur,

    Please let me know what you get when you have the chance to run the driver through the program.

    Thanks,
    Tim
     
  7. Tim Bargar

    Tim Bargar Agent

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    That is about the age of the ACI drivers I have.

    So should I not be concerned with port air velocity? Winisd pro says the velocity will be about 93 f/s @ 20Hz through a 4" diameter x 9" long port. The dimensions I gave earlier resulted from my effort to keep the air velocity below 18 f/s. Unibox returns a port dimension of 4" x 6" with a 11 m/s @ 20Hz, while another calculator returned similar dimensions but gave not air velocity.

    I am just trying to save some money and maintain marital bliss. My wife is cool with the expenses going into building a dedicated home theater, but is going to balk at any component purchases, especially a subwoofer since I already have two (I have two home built closed box subs with the two ACI drivers).

    I've experienced SVS performance and I'd like get that type of performance in my future home theater. I'd like to buy an SVS. But to save money, I want to see if I can get similar performance out of my two ACI drivers mounted in different enclosure types. If not, fine. If I can, then great. That is all I'm trying to do.
     
  8. ThomasW

    ThomasW Cinematographer

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    If you put both drivers in one box larger you'll get slightly better performance. Use 2-4" flared ports if you do that.

    FORGET about the mach and excursion numbers from WinISD....just build a ported box tune it to 18 or 19Hz.

    Remember that WinISD doesn't factor in room gain.... it also doesn't model accurately. Use UniBox if you have the MS Excel spreadsheet program
     
  9. Tim Bargar

    Tim Bargar Agent

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    That is what I was beginning to think. My experience with models, not speaker building models, is that their output can vary considerably. It is informative to see how model output varies among models given the same input data.

    I have excel, and have used it quite a bit in my line of work. So, I've been playing around with unibox a bit to see what I get.

    Thank you for posting the link to unibox. [​IMG]
     

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