Some time ago, I spoke with Eric at Earthworks about the difference between the TC30K and the M30. He said they are essentially the same mic. After some market research, Earthworks determined that people buying a measurement mic typically want a mic with a name that identifies it as such. This is the reason for the two different names. The M30 would work just as well for recording as it would for measurement; however, I think you might find that mic's self noise to be a bit much in quiet passages.