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How to correctly use WinISD
How to correctly use WinISD
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Old 8th August 2009, 09:22 AM   #1
Zero D is offline Zero D  United Kingdom
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Default How to correctly use WinISD

I've noticed a quite few people seem to be having all sorts of problems using WinISD when trying to design speaker cabs. So i thought i'd explain how i do it.

Enter the Thiele Small parameters from the drivers data sheet in the order you see in my screenie.

Click the image to open in full size.

A = Qes

B = Qms

C = Fs

D = Re

E = Vas

F = Pe

G = Xmax

H = BL

Pay VERY close attention to the terminology, as there are multiple choices available to choose from in WinISD. This is because not all manufactures list them identically. One incorrect entry and your design will we way off, and will NOT work as you hoped.

For example - Vas might be listed as 9.288 cubic feet, which is the same as 263.00 Liters in my screenie. If you carefully click on the appropriate position, in this case L as shown by the red arrow, you are able to change it to match what your data sheet shows.

Click the image to open in full size.

Also notice how the text in the white entry boxes are coloured. Green, Blue and Black.

Green = Manually entered data

Blue = Automatically calculated

Black = No data

If you Carefully follow the above advice, then you should be now be able to design boxes more confidently and accurately. I've been using WinISD for many years this way, with great success both commercially and privately.

Happy building and listening,


Zero D
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Old 8th August 2009, 10:16 AM   #2
col is offline col  Australia
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The best way to enter the data into the driver editor is to follow the directions from the Help menu. From the top menu bar go to "help", "contents", "using WinISD pro", "entering new driver data". Step-by-step instructions there.

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Old 8th August 2009, 01:04 PM   #3
GM is offline GM  United States
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Thanks for the effort! FYI, a tutorial here with some files folks can download as well as share yours. Some other good stuff too: http://www.hometheatershack.com/forums/diy-subwoofers/

Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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Old 9th August 2009, 04:33 PM   #4
Zero D is offline Zero D  United Kingdom
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Hi, unfortunately even with the helpfile included in WinISD, a lot of people still struggle with it, and some even give up trying. As there are many different possible permutations of entering the required data, and also different terminology used by companies, i thought it would be useful/helpful to show precisely how to accomplish a working design, for those that didn't already know.

By the way, thanks for your www and your very useful tools.


Thanks for the kind words, and the link.
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Old 9th August 2009, 11:30 PM   #5
PeteMcK is offline PeteMcK
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Hi Zero, very useful for beginners; just one question, I usually enter Sd and let WINISD calculate BL, can you see a problem with doing it this way?
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
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Old 10th August 2009, 07:11 PM   #6
Josh Ricci is offline Josh Ricci  United States
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I find it's best to use the most reliable parameters and enter them according to the instructions in the program. Things like RE, BL, SD, MMS...Parameters like FS, VAS etc. often vary quite a bit more between drivers. I don't worry about getting the parameters exactly like the manufacturer's specs. Small variations in a parameter or 2 like the qts, vas, fs, don't really affect the modeling appreciably. I'm talking about small differences like the VAS being 224L instead of 231L or the FS being 22.6hz instead of 23hz or the qts being 0.411 instead of 0.415. The real world driver variation from the manufacturer's median specs are usually much bigger than this.
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Old 10th August 2009, 10:17 PM   #7
Collo is offline Collo  Australia
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ZeroD, I think you are confusing me with user Col, who posted earlier. Still appreciate the thanks though.

I have a WinISD tips page that lists the following advice from one of the authors of WinISD....

Enter Qms, Re, Mms, Cms, Bl, Sd, hg, hc, Xlim (if available) and Pe.
Let the program auto-calculate the rest and don't change any of 'em.

This seems to work pretty well.
Ports rule!
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Old 11th August 2009, 03:46 PM   #8
Zero D is offline Zero D  United Kingdom
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Hi all.


Entering Sd and let WinISD calculate BL is fine, as there many ways to achieve the same results when entering the required data. I could have given multiple of examples of entering the values in different ways, but that would only have confused some people. So i had to choose one way to explain, which i know definately works.

Josh Ricci

Small amounts as you suggest, i agree won't make a lot of difference.


Ahh, you're not Col then. I saw the Oz flag and together with Col i presumed it was you lol. Anyway, nice to see you on here.


As you can see i now know who's who, sorry for the confusion with the names.
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Old 20th August 2009, 02:07 PM   #9
cixelsid is offline cixelsid  United States
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Although he didn't go into detail; Jack Hidley (someone who knows a thing or two about speaker design) posted on AVS that in the first few minutes of trying to use WinISD he noticed there were math errors in the program.

It might be a good idea to get this clarified since tutorials, tips and FAQs are rather pointless if the program itself is flawed.
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Old 19th April 2011, 07:36 PM   #10
loninappleton is offline loninappleton  United States
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This is an older thread but I d/led winisd pro .50 alpha from Softpedia. I previously had another winISD prog on here.

I have the driver params put in for one not on the list file name 'roland' (small 'r'). My goal is to get a port diameter and depth.

This has been impossible. And yes I have read the directions and even some additional how tos.

Is there any step by step instruction for Winisd freeware that is complete with screen shots?

This means not skipping anything and using something other than the canned help file which only uses drivers that are on the list.

Maybe the T/S prams for this old Roland are out of range. Here they are:

[quoting a previous note]

Zene posted these specs back then, so OB or leaky box are the obvious choices:

Roland 8" is/are: (Used Peak Inst. for test, only broke-in 12 hrs.)

Paper cone
Fs = 78.76 hz
Vas = 24.5 L/0.8652 cu ft
Re = 7.309
Le = .2462 mh
Qms = 5.772
Qes = 1.977
Qts = 1.473
Sd = 21.4 sq cm/3.317 sq in
BL = 0.4477 N/A (calc'd)
Spl 89.65 1w/1m
Pe = 30W



Some research is needed (Page 1) / FullRangeDriver Forum / Fullrangedriver Forum

[end quote]
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