https://disensors.com/product/4145-1-inch-free-field-microphone/
4145 1-inch Free-Field Microphone - Durham Instruments
Jun 11, 2019 - 2.6 Hz TO 18 kHz, 200V Polarization. Designed for low-level and laboratory free-field measurements, it is also suitable for sound pressure measurements in...
free field microphoneinchdurhaminstruments
https://norsonic.no/produkter/mikrofoner-forforsterkere/nor1239-free-field-microphone/
Nor1239 Free-field microphone - Norsonic
Aug 21, 2025 - The Nor1239 is a free-field 1/2-inch electret microphone conforming to the Class 1 specifications for sound level meters specified in IEC 61672-1 class 1.
free field microphone