# calculate a subwoofers Vd

Discussion in 'Speakers & Subwoofers' started by MikeDuke, Sep 7, 2004.

1. ### MikeDuke Stunt Coordinator

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If I have all of the Thiel specs for my driver, how do I try to figure out what the Vd (displacement) might be. Is there a site that does this for you?

Thanks

2. ### Edward J M Cinematographer

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It's basically the effective surface area of the driver (Sd) multiplied by the maximum linear travel Xmax, multiplied by 2 for one full stroke (both directions).

You might have to do some unit conversions to make it work out right, but the math isn't terribly challenging.

3. ### MikeDuke Stunt Coordinator

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4. ### MikeDuke Stunt Coordinator

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Does This look right?
Sd=551.5
Xmax=9mm
551.5 Sq cm * 9mm *2=9927cc
605 Cubic inches

Thanks again.
Forgive my ignorence
Mike D
I know what I like when I hear it.

5. ### dave alan Second Unit

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6. ### Edward J M Cinematographer

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551.5 cm2 x 9 mm (1cm/10mm) x 2 = 992.7 cm3

992.7 cm3 (1Liter/1000cm3) = 0.9927 Liters (the most common unit to express Vd)

or

992.7 cm3 (1in3/16.39cm3) = 60.57 in3

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