If you use a USB microphone such as the MiniDSP Umik, you may find a problem with your measured impulse response : the impulse itself is not clean and shows many peaks together instead of just one. This may come from USB problems : gliches or short drop-outs while recording …
Measurement microphones, electret, electrostatics or MEMS, are generally considered as minimum phase devices in the frequency range we are interested in. So the calibration file does not need to have phase included but those files are valid if phase column is after amplitude column (but we do prefer cal file …
For acoustic measurements, you really don’t need high sampling rate files to play or to record. So we choose to produce our sound files at 44.1 or 48kHz. For your recording, you can use any sample rate because the file will be resampled to 48kHz for analysis.