I want to determine the frequency response (magnitude, phase) of a microphone. I have another "good" reference microphone whose frequency response I know.
I understand that I can use a good speaker and measure the two mics simultaneously using white noise. Regarding the magnitude response, I can estimate the power-spectral densities by a method of averaged periodograms. Next, I can find the magnitude response of the device under test by subtracting the power spectral densities in logarithmic scaling and adding the known magnitude response of the reference microphone.
- Averaging over periodograms seems necessary to control the variance of the periodogram estimator. But what about the phase response? Does a similar inconsistency exist for the angle of the fft also?
- If I use an exponential sine sweep $x(t) \propto \sin(\omega_0 e^{a t} t)$, how do I obtain the frequency response? Do I average over the entire measurement time or do I do no averaging at all?
Edit: I did not explicitly state but implied that I perform the measurements in an anechoic room.