Measure Thiele-Small parameters?

Will Kort

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Running REW latest V.5.20 Beta 55 in the latest update of Win 10. The Thiele-Small Parameters tool does not seem to work. (there is a new dropdown field "Measurement Method" that is not shown in the online help). Calculate Parameters is greyed out until I enter at least one Manually Entered Value field and tab. However, clicking Calculate Parameters changes the button background to blue, but nothing happens (except Mb/Mb in lower left values change) and no results are displayed. I can measure loudspeaker impedance and phase, so the test rig is wired correctly and sound card is working. Anyone have any ideas? Thanks.
 

John Mulcahy

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The online help for the beta version is here, linked from the beta page. As a minimum the voice coil resistance needs to be entered to get any results. The help is also available in REW.
 

John Mulcahy

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My psychic powers are weak today :) so probably best attaching the mdat file you are using and I'll take a look.
 

John Mulcahy

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The mdat file is what you get when you save a measurement, .mdat is the extension for REW measurement files.
 

Will Kort

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Not sure if this will be useful, but I've attached a driver impedance and phase file. I don't have any measurements from the T-S tool because it won't run.
 

Attachments

John Mulcahy

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The TS params tool doesn't make measurements, it carries out calculations on measurements you ask it to use. I guess you didn't select a free air measurement in the tool, for the next build I have added a message if someone should do that. The simplified model parameters calculated for that measurement are incorrect for the current beta, but I have fixed that for the next beta. Here is the result for that single measurement, only a limited set of parameters can be calculated without additional measurements.

33025
 

Will Kort

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Got it - thanks! I am primarily interested in resonant freq. and total Q, so the single sweep works for me.
 
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