Acoustic test for the sloshing noise in a tank

[georgeous678]

I am currently doing an acoustic experiment, testing the sloshing noise made by the fluid content in a tank. My software and microphone gives me all the outputs from the sloshing noise but not the loudness calculation. I am needing a figure for every test to key into my statistical software and compare all my different results. How do I calculate the average noise? or even better a certain point in the noise from the time series graph?

 

[James Leighe]

I am currently doing an acoustic experiment, testing the sloshing noise made by the fluid content in a tank. My software and microphone gives me all the outputs from the sloshing noise but not the loudness calculation. I am needing a figure for every test to key into my statistical software and compare all my different results. How do I calculate the average noise? or even better a certain point in the noise from the time series graph?

Integrate the absolute values of the graph using Riemann sums between two time intervals and divide by the difference in time?

I don't know of any software that does things like that however. But you could write a little script or something I dunno.

 

[Andy Resnick]

This could be a pretty cool experiment. Measuring absolute SPL values requires (AFAIK) a calibrated microphone, I've used a Brüel & Kjær setup. That's probably overkill for your application- I would work with relative measurements rather than absolute.

Surely you can calculate the average signal from your data- but don't toss away any frequency information: do a Fourier transform on the signal to get a spectrum, I bet that will be interesting, too.