Is not the sample values proportional to the voltage? Then according to this website, 20 should be used instead of 10? Or am I misunderstanding what you mean? Thank you in advance! Thanks a lot for your e-mail, the lines of code and the link. Am I missing something in my understanding of this or could this be a bug in Sonic Visualiser? There also seems to be a similar difference in the spectrum view when I compare Sonic Visualiser to Adobe Audition. Thank you very much in advance! Best regards, Christofer ,_Sv1-devel mailing Could it be the case that Sonic Visualiser calculates the dB values using 10*log10(input)? It was my understanding that dB values usually are calculated from sample values using 20*log10(input). Similarly, if I generate a sine wave at -40 dBFS in Adobe Audition, Sonic Visualiser displays the level -20 dBFS. If I generate a pure sine wave at say -20 dBFS in Adobe Audition, Sonic Visualiser displays the level -10 dBFS in the waveform view. ![]() ![]() Is not the sample values proportional to the voltage? Then according to this website, 20 should be used instead of 10? Or am I misunderstanding what you mean? Thank you in advance! Best regards, Christofer From: 20 January 2021 18:32To: Christofer Bustad Re: dBFS Hello, Well, if you check the source code of Sonic Visualiser you could spot this lines.AudioLevel - float dB = 10 * log10f(multiplier) SpectrumLayer - value = 10.f * log10f(value) so if you are saying why does Sonic Visualiser use 10 instead 20 you may check here : Regards,Mehmet , 17:12, "Christofer Bustad" there, Thank you to all who contributed to this great and very useful piece of open-source software. I wonder if someone may help me to understand something. power goes as the square of the pressure then factor of 10 applies.I reviewed that Sonic Visualiser uses also "20 * log10" in some cases - did not check yet when and why.I am not familiar with Adobe Audition and its settings.I will try and see if I can get the same results as you.Could you specify what versions ( S.Visualiser and A.Audition ) you work on.Note: I am also a student / please correct me any time. RegardsMehmet , 21:38, "Christofer Bustad" Mehmet, Thanks a lot for your e-mail, the lines of code and the link. ![]() Dear Christofer, I believe sample values proportional to pressure on microphones which we measure as voltage/current and call it amplitude values, hence the formula with the factor of 20 applies.
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