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Negative sound pressure levels over a certain frequency

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I am testing the sound pressure levels of a piezo transducer (using PZT-4 as piezo transducer) at different frequencies.

The one used is: https://www.steminc.com/PZT/en/piezoelectric-disc-25x85mm-s-235-khz

And, when simulating the sound pressure levels I get negative result above 142 kHz. The resonans frequency for this piezoelectric-disc is 235 kHz.

Does anybody know where I did something wrong?

Best regards, Kim

The Generated Graph of Frequencies


2 Replies Last Post Oct 5, 2019, 11:08 a.m. EDT
Edgar J. Kaiser Certified Consultant

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Posted: 5 years ago Oct 5, 2019, 5:49 a.m. EDT

Kim,

you are plotting dB, that is 10*log10(p/pref). So the sound pressure level is not turning negative, only very small.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Kim, you are plotting dB, that is 10*log10(p/pref). So the sound pressure level is not turning negative, only very small. Cheers Edgar

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Posted: 5 years ago Oct 5, 2019, 11:08 a.m. EDT
Updated: 5 years ago Oct 5, 2019, 7:08 a.m. EDT

Edgar,

Thank you very much! I must have had a late nigth out yesterday ...

Cheers Kim

Edgar, Thank you very much! I must have had a late nigth out yesterday ... Cheers Kim

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