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Where on winisd do i check for xmax?

Discussion in 'Home Theater Projects' started by Anthony*gw, Nov 20, 2003.

  1. Anthony*gw

    Anthony*gw Well-Known Member

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    Greetings all, I am using winisd pro and have designed a 140L enclosure for a shiva driver tuned to 20hz,(box is already completed,just waiting for driver). I think i understand alot about the software,but how do i check to see if a driver is close to xmax in a certain alignment(140L,shiva)?
    It will be powered by a 2ch stereo amp 200wpc and 300wpc 4ohm load.i will be wiring the driver in parallel so it will be 300w going to the driver.could someone explain how much power it will take to pass the xmax on the shiva driver in this size box(140L)and at what frequencies?
     
  2. Pete Mazz

    Pete Mazz Well-Known Member

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    Cone excursion. WinIsd uses point to point, so if your driver has a 1 way Xmax of 15mm, look for where the excursion graph shows 30mm.

    Pete
     
  3. Anthony*gw

    Anthony*gw Well-Known Member

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    Thanks pete,
     
  4. RichardHOS

    RichardHOS Well-Known Member

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    I'm just using the standard version, and I haven't played around with WinISD as much as LspCAD, but I've never seen the plot for cone excursion.

    ??
     
  5. Anthony*gw

    Anthony*gw Well-Known Member

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  6. Anthony*gw

    Anthony*gw Well-Known Member

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    I played with winisdpro and check the cone excursion for my enclosure and got 2.043mm at 30hz,thats the highest peak between 20hz-50hz and 2.043mm at 17hz.it just keeps getting higher when you go below 17hz.so i am basically getting the same reading at 17hz and 30hz.what do these numbers say? at 17hz and 30hz my shiva will most likely bottom out at high volumes?[​IMG]
     
  7. Pete Mazz

    Pete Mazz Well-Known Member

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    Looks like the Cone Excursion shows one way Xmax now.

    Click on the signal tab and under System Input Power, enter, in your case 300W. The CE graph should now show overexcursion at just above and below tuning. Entering 225W into Input Power would run it to full excursion....theoretically.

    Pete
     
  8. michael-e

    michael-e Active Member

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    Dont forget,you dont HAVE to use every mm of excursion as every mm you go,will be more distortion.

    Also the suspension will be less linear moving further.

    thats if your looking for low distortion..for HT its not so critical

    [​IMG]
     
  9. Brian Tatnall

    Brian Tatnall Well-Known Member

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  10. michael-e

    michael-e Active Member

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    Hold up
    Woofers seem to distort differently even with similar xmaxes''

    Xmax is the smaller of Xmag and Xsus,
    and that is where its 70% of BL or
    70% of suspension linearity

    that speaks NOTHING directly, of what the speaker distortion output is!

    look at mfk-projects.com
    the woofers are all at the same conditions,and distort differently yet no where near xmax(i think)

    Non linear suspension will be worrying below Fs(eg below Fcb in sealed boxes)

    i would love to test similar speakers like that,id make sure the output DbA was constant rather than constant Vin ...

    i may not be right but its just my opinion...
    Cheers![​IMG]
     
  11. Anthony*gw

    Anthony*gw Well-Known Member

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    Hey thanks for all the input guys greatly appreciated
     
  12. Anthony*gw

    Anthony*gw Well-Known Member

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  13. Anthony*gw

    Anthony*gw Well-Known Member

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  14. Anthony*gw

    Anthony*gw Well-Known Member

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    My bad,i saw it.forget what i said above[​IMG]
     
  15. Anthony*gw

    Anthony*gw Well-Known Member

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    back with some numbers:

    at 30hz,winisdpro gives me a reading of 35mm which is the highest point on the graph between 20hz-50hz,30hz being the peak .and i am getting the same reading at 17hz(35mm)after 17hz it just keeps going higher and higher,no worry though, for i am not really interested in frequencies under 17hz.keep in mind that i built a 140L 80/20(HT/music)tuned to 20hz using one 4" flared port,will be using the shiva and throwing 300watts at it.
    tell me if i got this right.at the frequencies 30hz and 17hz the driver will be passing it's xmax and with enough power i can bottom out my driver? should i worry if my driver reaches 35mm
     
  16. Brian Tatnall

    Brian Tatnall Well-Known Member

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  17. michael-e

    michael-e Active Member

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    point 1
    if xmax directly was related to THD,then why is it defined by % of BL or kms not THD @ mm excursion...

    Does 70% BL on one woofer, and 70% BL on another,have equal THD at that point/??

    point 2

    www.linkwitzlab.com
    'thor' subwoofer
    see his measurements on the subwoofer he made and distortion requirements

    I think that THD
     
  18. Brian Tatnall

    Brian Tatnall Well-Known Member

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    Point 1
     
  19. michael-e

    michael-e Active Member

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    lol,i realised we are discussing this in this guys thread,when it doesnt really concern him,so will pursue this discussion with PMs rather than thread-hog.

    Cheers Brian
     
  20. Brian Tatnall

    Brian Tatnall Well-Known Member

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    Excellent idea Michael. YGPM.
     

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