1/2″ Prepolarized Random Incidence Microphone GRAS 40AQ 3.15Hz~12.5kHz

Introduction

• The 40AQ is an IEC 61094 WS2P/D ½” prepolarized random-incidence microphone with rear-venting. Read about the externally polarized equivalent 40AR.
• It is a high-precision condenser microphone made according to IEC 61094-4 requirements, optimized to measure sound correctly in random, diffuse, and reverberant sound fields. It is extremely robust and reliable and can measure sound pressure levels up to 148 dB in the range of 3.15 Hz to 16 kHz.
• 40AQ is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response. 

Typical applications and use

• The 40AQ is optimized to measure sound levels correctly in random (diffuse) sound fields. e.g. caused by multiple sound sources or hard reverberant surfaces. Random incidence microphones are used e.g. inside vehicles.
• 40AQ is included in the GRAS46AQ Random-incidence microphone set.

Compatibility

• The 40AQ requires a standardized 1/2″ or 1/4″ CCP preamplifier and an input module that supports this technology with a BNC, SMB, or Microdot connector.

System verification

• For daily verification and check of your measurement setup, we recommend using a calibrator like GRAS 42AG Multifunction Sound Level Calibrator.
• For proper sensitivity calibration, we recommend using a pistonphone like GRAS Intelligent Pistonphone 42AP.

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 gras/calib.