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I'm using Welch's method (pwelch, in octave) to get the PSD of a recorded sound signal (i.e. pressure level vs. time). I then took the PSD data and took the sum of the amplitude in each octave band (1/3 octave). My question is: how can I convert the PSD data to a sound pressure level (per band, or per frequency if I do it before 1/3 octave sort/sum). For an overall SPL, I can take the pre-PSD estimation data and calculate via the equation Lp = 20 log10(Prms/Pref).

Any suggestions?

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You need to factor in you'er transduce characteristics to do anything meaningful with PSD numbers. –  user2718 Feb 22 '13 at 20:43
In what way? The PSD values are derived from the scaled transducer output, i.e have already been converted from voltage to pressure. –  user3836 Feb 22 '13 at 22:27
Just want to make sure you have your calibration right. You should check your results at various levels and frequency bands with a calibrated SPL meter to make sure. Someone posted this!msg/… which may be helpful. –  user2718 Feb 24 '13 at 23:36

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