Measuring microphone Signal to Noise ratio (SNR) with A-weighting Foreword: I have already read Applying A-weighting and user @endolith's  A-weighting code

I would like to measure the SNR of a microphone with the same method applied by the main manufacturers, that is displayed in their datasheets (example here with Neumann's U87 technical spec):



Here is how I plan to do it:


Play a continuous 1 kHz sine signal with a studio monitor loudspeaker (ideally in an anechoic room)
Adjust the playback volume such that the measured volume, close to the microphone, is 94 dB SPL, by using a sound level SPL meter device

Question here: should it be 94 dB SPL RMS or peak? (For a sine there's a difference of ~ 3 dB between RMS and peak)
Record the audio signal with a digital audio interface
Stop the playback of the sine and also record some silence (and thus some microphone noise: that is precisely what we want to measure!)
Normalize the recorded WAV file to 0 dB FS (so this will take the peak of the signal in consideration)

Is this step correct? It seems that a normalization is required here; if no normalization is done, the result SNR would depend on the preamp input gain!
Apply the A-weighting or CCIR-weighting (also called ITU-R 468 weighting), for example with endolith's code here
Compute the RMS of the A-weighted signal, during the silence/noise-only part.
This will be the final "Signal-to-noise ratio, A-weighted (re. 94 dB SPL) of the microphone".


Is this correct?

Here is a WAV file I recorded with the method described here. I'm curious to find how to find the A-weighted SNR of this microphone.
IEC 801-21-20 Defines sound pressure as the RMS of of the instantaneous pressure, and as far as I know all meters use RMS.  The problem you have in your implementation is that you are normalizing the peak value of the active region but measuring the RMS of the inactive part. As you described, for sine waves the RMS is 3dB less than the peak.  You could take the Difference between the RMS in the active to the inactive regions.  Or you could assume that the active RMS is -3dB and use that instead.  Otherwise you should be good to go.