June 24, 2010

WinISD - entering new driver data

Entering new driver data is a little tricky in WinISD pro. As the numbers are calculated, if you simply enter in all the parameters as shown in the data sheet, it won't work. A simple thing like rounding off the numbers will mess it up. You can find detailed instructions in the help files, but my video tutorial will give you the gist quickly.

A few tips:

1. Enter in the parameters in the exact order shown

2. If one parameter is missing, let the program calculate it from the others

3. Let the program automatically calculate some of the parameters

1. First enter mms and cms then click in fs which will then be calculated

In the tutorial, fs but not cms is provided.

2. Enter sd, bl and re

3. Enter Rms or Qms

If you only have one, then click on the other after entering, so it will be calculated

4. Enter xmax and PE

This is required for max SPL charts. If you don't have the power handling, you might make a reasonable guess. You might also choose to enter "music power" which is typically twice the typical nominal RMS rating.

5. Do a quick check of Qts, VAS and SPL to see that they are reasonably close to the specs. Don't worry about small changes as they aren't critical.

Note: Don't enter Le (voice coil inductance). Often this will result in simulations showing early roll off. Some drivers have a fairly high inductance of around 4mH. This will cause significant roll off much greater than measurements show. A null value here is usually more accurate.


  1. I cant get my driver into a project... It doesn't give an error, it just doesn't go into my project.


  2. Everytime, it says, "parameter error list"

    Not really usefull!!!

  3. Then you need to clear everything and start again, following the instructions carefully. You have made a mistake. You must let it calculate certain parameters even if you have them from a datasheet, otherwise it will think there is a problem.

  4. I´ve had everything did what instructions says.

    The problem, he calculate the Qes and Qts not correct..

    I can use it but with different Qts & Qes.

    When I change the data by my self, the program says: "parameter error list"...

    I try to use the RE Audio REX8 Subwoofer.
    Try it if you want, here are the TSP:
    Electrical Q Value -Qes: 0.38
    Mechanical Q Value -Qms: 4.21
    Total Speaker Q Value -Qts: 0.34
    Free Air Resonance -Fs: 22.8 Hz
    Equivalent Compliance -Vas: 27.1 liters
    One-Way, Linear Excursion -Xmax: 12 mm
    Efficiency -SPL 1W/1m: 81.2 dB SPL
    Effective Piston Area -Sd: 195 cm^2
    DC Resistance -Re: 3.2 ohm
    Nominal Impedance -Znom: Dual 4 ohm
    Thermal Power Handling -Pe: 175 W
    Force Factor -Bl: 15.4

    Mounting Depth - 4.5 inch
    Mounting Hole Diameter - 7.3 inch
    Overall Diameter - 8.7 inch
    Bolt Hole Circle - 8 inch
    Motor Width - 4.875 inch
    Motor Depth - 1.9 inch
    Basket Depth - 2.4 inch
    Displacement - 0.07 cu. ft.
    Weight - 6.2 lbs.

    thanks :)

  5. The problem is that they didn't give you enough parameters. I can get it to work with the right Q values, but it makes VAS 13L. Try entering fs, Qms, Qes, SD, BL then let it calculate VAS, CMS and RMS. Enter xmax and PE ... that should work with some compromise on the VAS. You could always press the supplier for more parameters. They really should give adequate parameters for a proper simulation.


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