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Discussion Starter #1 (Edited)
Hi,

I've done an impedance measurement of a driver I had lying around (using a circuit I designed to buffer output and input stages). This is the .mdat file. I don't have a weighted measurement, but that's OK for now.

I'm trying to have REW calculate some T/S parameters, but nothing happens. The button does become clickable. There are no error messages in the console.

The manual data are:

  • Rdc = 5
  • area = 63.6 cm² (9 cm diameter)

No matter what I enter manually, it still does nothing.

Is this a bug in the program, or am I doing something wrong? I guess it should at least inform me about what's wrong, right?

I'm using REW 5.00.
 

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Discussion Starter #3 (Edited)
Does that mean that you can't get any result with just one measurement? The help file suggests you only need the second measurement for Vas and some others.

I did try making two measurements, BTW, but without the actual added weight. It still didn't help.

Edit: The manual states:

These parameters can also be calculated for any single measurement, without requiring a secondary measurement to be selected. The LP figure and the MMS, CMS, RMS, VAS, Bl and Eta (efficiency) figures in the third column can only be calculated using both measurements.
 

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Sorry, I didn't see that quote. I didn't ever try it with one measurement.

I know that the trace needs to be pretty clean and yours doesen't look too bad. There is that low end peak that shouldn't be there and maybe that is the issue?

You may want to try a sweep starting just above that, maybe 5 Hz or so. If that isn't the problem I am out of ideas.

EDIT:
I just tried the cal with your data on my PC and It seemed to work okay. Maybe there is just a wrong setting when you tried?

Untitled.png
 

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Discussion Starter #5
And you're using the beta version? I can't get it to do anything, no matter what I enter. The form just blinks once when I push the button, and then nothing.
 

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Yes, 5.01 Beta 17. Some of the earlier versions had a problem with the calculation.

Sorry, that I don't know what else may have gone wrong. Hopefully someone else has an idea.
 

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Discussion Starter #8
Make sure you select the measurement in the 'free air measurement' drop down.
I did, of course. When I don't have it selected, the button doesn't even become clickable.

I just tried the beta. It does work there.

Is there stuff that is known not to work in the beta that I should be aware of?
 

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Thank you, I also had a problem with the calculations TS parameters in version 5.0. Beta version from the link above works.
 
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