With the miniDSP UMIK-1, you have an easy way to get a precise acoustic measurement. First download the calibration file for your microphone. Each microphone has a unique calibration file, which define the specific frequency characteristics of each individual microphone. The calibration file ensures that your microphone is as accurate as possible. Go to the UMIK-1 page and enter your microphone's serial number. It is in the form xxx-yyyy and labeled on the microphone. There are 2 versions of of the calibration files available. One version for the microphone directly aimed at the speakers (stereo setup) and one 90 degree version for the microphone aimed at the ceiling (for surround sound setup). Use “Save As” in your browser to save the numbers as a file e.g. 7000343.txt.

Connect the UMIK-1 to your computer using the supplied USB cable. Once installed, start REW. You will see a screen asking if you want to use the UMIK-1. Click on Yes. (If you don't get this screen, go to the REW Preferences window and set the Sample Rate to 48 kHz.)

USB mics can be used with the acoustic timing reference feature. Turn on the “Adjust clock with acoustic ref” Analysis option to have REW try and compensate for the variations. This will be usefull for Phase measurements, that rely on accurate timing.

The UMIK is automatically calibrated by REW for sound level (this information is in the calibration file). But you need to set your system to generate a suitable signal level. Click on the Signal Generator button and set the parameters like illustrated below. Position your microphone at the listening position and turn the volume of your system down. Then click on the Play button (green triangle), and turn the volume up until the test signal is at a comfortable level. Now open the REW SPL Meter. Click on the red button in the lower right corner to turn it on, and adjust your system volume until the meter reads about 75 dB.