Question Regarding WINISD Pro

[evilskillit]

I notice that when I put speakers into WINISD, in this case subwoofers, that the auto calculated values are sometimes pretty different than what the manufacturers list. I was wondering which generally gives a more accurate picture of how a driver will work. I know that WINISD calculates the values according to the formulas that describe the parameters and manufacturers are known to fudge numbers in their favor, so I would be more inclined to trust WINISD but I don't know for sure.

For example when putting in the Dayton 15" IB Woofer IB385-8

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-455

Using these specs

http://www.parts-express.com/pdf/295-455s.pdf

If I enter in every value the curve is pretty different than if I put in,
Qes, Qts, Vas, Mms, Re, BL, Xmax and Pe and let the rest of the values autocalculate. And some of the auto calculated values are hugely different than what the manufacturer lists. EG, autocalculated Vd is like 2.04 manufacturer listed is like 1171.7

*edit, I may just have not been putting the parameters in, in the best order. Its been a while since I have used WINISD so I went to the helpfile and checked the method for inputting a driver and the results I'm getting make alot more sense now.*

Sorry for posting before I checked to make sure my head wasn't just stuck up my own butt.

Pictures follow,

[lunchmoney]

Are you entering the figures in the correct order? The software is finicky about this...

In the help section of Winisd it tells you the order in which to enter the figures.

[evilskillit]

Yeah, see edit, I'm a fool, thanks for helping.

Also I think there is something wrong with either dayton's specs or WINISD when calculating VD, Dayton Audio specifies it in litres but when I change the formatting in WINISD to cm^2 then it matches dayton's figure in litres, so someone is using the wrong units, probably dayton.

[minkuni]

Dayton do not have their metric units straight. A 15" woofer may move a lot of air, but a figure just shy of 1200 liters is rather optimistic :B (1200 liters = 1.2m^3 = 42.4 cu.ft.)

Edit: The correct units are, as you have figured out, cubic centimeters (cm^3). A bit confusing since the VAS is correctly indicated at 250 liters.