CSL will cal the Dayton EMM/UMM or UMIK microphones. The ECM8000 has been having issues (see the CSL website). FWIFM, after a little research, I went with a CSL-calibrated UMIK-1. http://cross-spectrum.com/measuremen...ated_umik.html

CSL also sells a Galaxy CM-140 SPL meter with freq file. http://www.cross-spectrum.com/measur...ted_cm140.html

My Earthworks M30 is very nice but pretty expensive. It is not a USB mic and requires phantom power so you also have to have a preamp with it. http://www.earthworksaudio.com/micro.../m-series/m30/ Mine is probably overdue for a recal.

They now make a battery-powered version with built-in preamp but it is not USB either: http://www.earthworksaudio.com/micro...-series/m30bx/

I had a B&K but got rid of it ages ago (should have kept it!) Bought the Earthworks a while back when I was helping install a sound system for our church (before REW and USB mics were around).

HTH - Don