Introduction
- GRAS 40AF is a high-precision condenser microphone made according to IEC 61094-4 requirements. The 40AF’s design is based on the original reference ½” pressure microphone, but optimized for free-field measurements with a 12 dB increase of the sensitivity. The result is a nominal sensitivity of 50 mV/Pa, slightly longer microphone housing, and a natural reduced dynamic range.
- It can be used for Type 0 and Type 1 measurements.
- 40AF is the perfect free-field complement to the GRAS 40AP ½” Ext. Polarized Pressure Microphone.
- 40AF is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity, pressure, and corrected free-field frequency responses.
Typical applications and use
- The properties and robust design make 40AF the natural choice for an all-round free-field, high sensitive microphone suitable for both field-work and laboratory measurements.
- The high sensitivity and reliability has made 40AF the preferred measurement microphone for sound level meters/analyzers with 200 V polarization voltage option and, as such, enables IEC 61672 Class 1 measurements.
Compatibility
- The 40AF requires a standardized ½” or ¼” LEMO preamplifier and an input module that supports this technology with a 7-pin LEMO connector.
System verification
- For daily verification and check of your measurement setup, we recommend using a calibrator like GRAS 42AG Sound Level Calibrator.
- For proper sensitivity calibration, we recommend using a pistonphone like GRAS 42AP Intelligent Pistonphone.
Calibration
- When leaving the factory, all GRAS microphones have been calibrated in a controlled laboratory environment using traceable calibration equipment. Depending on the use, measurement environment and internal quality control programs we recommend that the microphone is recalibrated at least once a year.
- We offer two kinds of calibration as an optional after-sales service: GRAS Traceable Calibration and GRAS Accredited Calibration.
- GRAS Traceable Calibration is a traceable calibration performed by trained personnel under controlled conditions according to established procedures and standards. This is identical to the rigorous calibration that all GRAS microphones are subjected to as an integral part of our quality assurance.
- GRAS Accredited Calibration is performed by the GRAS Accredited Calibration Laboratory that has been accredited in accordance with ISO 17025 by DANAK, the Danish Accreditation Fund.
- If you want a new microphone set delivered with an accredited calibration in stead of the default factory calibration, specify this when ordering.
- Learn more at calibration.