I found this information on a 3rd party mic verification and calibration tester called Cross Spectrum Labs regarding the Behringer ECM8000. BUYER BEWARE!!!
Effective immediately, Cross·Spectrum has ceased selling calibrated Behringer ECM8000 microphones. The quality of ECM8000 microphones has deteriorated to the point that we can no longer justify the effort in dealing with non-functioning units or mics with extremely abnormal frequency responses.
If the reason you are going to use a measurement mic is to make accurate measurements, what good will an inferior mic do to reach that goal? Consider one of the other inexpensive mics on the market with a better track record. For example, Cross Spectrum Labs will verify and calibrate a Dayton EMM-6 microphone.
Calibrated Dayton EMM-6 microphones
We are now selling calibrated Dayton Audio EMM-6 measurement microphones on an ongoing basis.
These microphones are similar (but not identical as you may read on some forums) to the Behringer ECM8000 and the stock units come with on-axis calibration curves.
We provide the following value-added services over the stock Dayton EMM-6 microphones:
The calibration curve provided by Dayton is in the range of 20 Hz to 20 kHz. We provide calibration files (.FRD format) on a USB thumbdrive for use in many popular audio measurement programs. Additionally, our cal files range from 5 Hz to 25 kHz to encompass the low bass and high treble regions that many audiophiles, professionals and home theater aficionados require.
Our own microphone measurements indicate that the data sheets included with the mics may not be representative of the EMM-6’s individual performance. As shown in the second link, our measurement methodology compares favorably with the results generated by a NVLAP NIST-traceable laboratory so you can be confident that your data are reliable.
As with our calibrated ECM8000 microphones, each EMM-6 microphone is calibrated against an ANSI-certified reference microphone. Each microphone will be shipped with the following:
Dayton Audio EMM-6 microphone with windscreen, case, and microphone clip
Microphone characterization report ( “Basic+” sample/ “Premium+” sample) with individually measured on-axis (0°) frequency response
“Premium” calibrated microphones will also include polar response, sensitivity, and noise floor
“Basic-Plus” and “Premium-Plus” microphones include frequency response curves at 45° and 90° angles of incidence
USB thumbdrive with frequency response data (.FRD format) and polar response data (Excel and .CSV formats, “Premium” calibrated microphones only)
Prices start at $75 plus shipping for “Basic+” calibrated microphones. Click the “Pricing” tab for information on domestic and international shipping rates.