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Negative Decibel Levels in Results

Posted Mar 28, 2017, 5:31 p.m. EDT Acoustics & Vibrations, Results & Visualization Version 5.2a 2 Replies

Cameron Guerette
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Hello,

I am running an acoustic analysis on a high frequency horn for a school project but my results are strange. It shows that as the air moves through the horn, the decibel levels quickly drop and once it is completely out of the mouth, the values become negative. Is there something wrong with my program? Any advice will help.

Thank you,
Cam
2 Replies Last Post Mar 28, 2017, 10:30 p.m. EDT
Cameron Guerette
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Posted: 7 years ago Mar 28, 2017, 5:32 p.m. EDT
I also cant make my velocity propagate explicitly through the horn, it sort of radiates outward. Any help with this will also be appreciated.
I also cant make my velocity propagate explicitly through the horn, it sort of radiates outward. Any help with this will also be appreciated.
Dave Greve Certified Consultant
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Posted: 7 years ago Mar 28, 2017, 10:30 p.m. EDT
You need to understand the definition of dB

dB = 10 log (P/Pref)

if P < Pref dB < 0. Pref is an arbitrarily chosen reference level.
You need to understand the definition of dB dB = 10 log (P/Pref) if P < Pref dB < 0. Pref is an arbitrarily chosen reference level.

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