T he CM-150 is a ½-inch-diameter (12.7-mm), omnidirectional electretcondenser microphone. It is intended for professional recording, free-field measurement and sound-level measurement. Because of its pre-aged titanium diaphragm, the CM-150 is extremely stable over a wide range of environmental conditions. The CM-150 has a very flat, wide-range frequency response. The mic is supplied with a proof-of-performance sheet, which shows frequency response and sensitivity. This information can be used to calibrate the microphone. The mic capsule grille fits into a Bruel & Kjaer 4220 pistonphone or similar microphone calibrator. When used for recording, the CM-150 sounds natural and accurate. It preserves the delicate timbre of acoustic instruments, yet can reproduce all the power of a pipe organ. The off-axis response is also smooth, so any leakage picked up has little coloration. Self-noise is low, permitting clean recordings — especially with close miking. The mic can handle very loud sounds (127 dB SPL) without distortion. It is protected against static and RFI. The output is balanced, low impedance, which allows long cable runs without hum pickup or high-frequency loss. Powering is by 18-48 volt phantom power. An included foam windscreen reduces wind noise outdoors.