The new SoundMeter apps also support the Dayton UMM-6 USB measurement microphone. When the UMM-6 is detected, the user will be prompted to enter its serial number, which is typically printed on a label on the UMM-6. If a valid serial number is entered, SoundMeter will automatically download a calibration file from Dayton's website and set the microphone sensitivity based on the information in the file.
Note: The Dayton UMM-6 must be connected to your iOS device via Apple's USB camera adapter (either for Lightning or 30-pin dock connector, depending on your device). Sometimes the UMM-6 shows up in iOS as USB PnP Sound Device. If that happens, unplugging the UMM-6 and plugging it back in will generally solve the problem (it may take 2 or 3 tries). When properly connected, "UMM-6″ will appear as the input device name in SoundMeter's toolbar (at the top of the screen).