Octave Analysis - Overall

Hi,

I made some acoustic analysis and I used Octave analysis with Overall calculation type.

Could you explain me how this option works? How is obtained the unique spectra with this option?

Another question.

When I open the acquisition I can see the spectra like in the picture I attached you. In this case, for instance, the value of microphone 4 at 970 Hz is 100,94 dB(A).

If I go in setup of the channel and click OK without modifying the options, the spectra are recalculated but the spectra are not the same. Indeed the value of microphone 4 at 970 Hz is 102,15 dB(A).

Could you explain me this, please?

Thank you

Dear Mr. Esposito

Overall averaging means that you get one value per measurement. Spectrum from Octave analysis is averaged through the measurement.

True octave filters exactly represent the filter sets defined by the IEC 61260 standards and give the user real-time response for vivid live visualization of data, crucial for advanced acoustic analysis

Synthesized Octave analysis uses FFTs as a base and calculates octave spectrum from the FFT spectrum.

https://dewesoft.com/applications/nvh-testing/octave-band-analysis

For different values, it might happen that recalculation is done on a different time window, resulting in different results.

Would it be possible for you to send us the data file so we can check the behavior?

Best regards,