Ready to align your system? Don’t rely on just any old reference microphone. Trust Earthworks. These guys have some of the most accurate microphones on the planet. This is a FIRST-CLASS reference microphone. Use it with your audio-band measurement system to get honest results, so you can tune accordingly. Earthworks M30 Omnidirectional Reference Microphone Features at a Glance: Small-diaphragm condenser reference microphone Features an omnidirectional pickup pattern Picks up an extremely accurate frequency response from 9Hz-30kHz Includes Electronic Calibration Files Requires +48V phantom