I have a broadband noise source based on a 24V Zener diode that looks like:-
You'll notice that it's asymmetric about 0V, but let's ignore that for ease of calculation. The noise is buffered prior to sampling with a TL081 op amp that has a bandwidth product of 3MHz. I think that makes 3MHz the frequency choke point within my little circuit. The Ampl value of 1.02V is actually a peak to peak measurement.
How can I determine the RMS noise level for only the audio range?