Here's our very precise, reliably repeatable and completely scientific way to attach a measurement mic to a Telefunken S-600
bearing (sorry, couldn't resist the joke).
Consumer electret microphones present 3 significant problems. First, the data they return below 50Hz makes no sense. For the task at hand, we certainly can live with truncated LF data.
Second, they are remarkably sensitive. At maximum gain, the mic attached to the turntable main bearing easily picked up conversations 3 rooms away. A door slammed at the other side of a building drove a DAQ into clipping. Car passing by on the street filled the data with noise. Because of that, all the measurements had to be done late at night, and we didn't do as many as we wanted to.
Third, the microphone and preamp turned out to be quite noisy. Fortunately, this noise is easy to subtract from the signal. Here's what the microphone, preamp and DAQ noise taken at 3 am looks like: