I looked at the coherence between the Microphone in the PSL (PEM-AS_MIC) and the MC_F channel.
We want to use a microphone to do Wiener/Adaptive noise cancellation on the MC and so we need to
have a coherence of more than ~0.1 in order for that to have any useful effect.
The attached plot shows the spectrum and coherence with and without the HEPA turned up. As you can
see, the HEPA noise is just barely noticeable in this microphone. 
We will need to get something with at least 20 dB more sensitivity.:P |