Problem with TSP calc -> mass method but REM assumes sealed box

1818 Views 6 Replies 2 Participants Last post by Wolfson, Apr 13, 2017

Wolfson

Discussion Starter · Apr 7, 2017

First of all: 1000 Thanks to the authors of the great tool REM!

I am exploring the functionality of REM and got stuck in computing the Thiele Small Parameters.
I've made the following measurements:

free air:

+10g

The result is then the following:

That is odd, since fs is clearly lower when adding the extra mass. I've found that thread, where someone described a similar problem, but the other way around. This was due to a bug in version REW V5.01 Beta 22, but I am using V5.18.

I also tried to add a bit more (50 g) and got this measurement:

with the following result:

What could I do?
Thanks in advance for every help!

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JohnM

· #2 · Apr 7, 2017

Can you attach the measurements, please?

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Wolfson

Discussion Starter · #3 · Apr 10, 2017

@JohnM: sorry for the late reply. I attached the measurements. The last three are the mentioned relevant ones.

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JohnM

· #4 · Apr 10, 2017

There is something very strange with the phase in those measurements, it shows the effect of a big time delay. How is your measurement system connected? Is there anything in the measurement path that would have a time delay?

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Wolfson

Discussion Starter · #5 · Apr 11, 2017

Mh, not really. I use the build in soundcard and calibrated it according to the description in the help. The calibration measurement is included in the file I attached. As a sound driver I use the asio4all. To connect the loudspeaker driver to the soundcard, I use some cables and cable adapters, that's it. I will do some more testing to investigate the phase problem...

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JohnM

· #6 · Apr 11, 2017

There's no need or benefit to using ASIO4All for this, it has value when using HDMI as the individual channels are then accessible but for other use it really doesn't add anything. Try with the Java drivers and see if the behaviour is correct then.

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Wolfson

Discussion Starter · #7 · Apr 13, 2017

Hey JohnM, I used the Java drivers and as you guessed everything works now :smile:
Thank you very much for your extremly fast and competent help and again for this great tool!
Best wishes from the black forest, Wolfson

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Problem with TSP calc -> mass method but REM assumes sealed box

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