G.R.A.S. 40AQ 1/2" Prepolarized Random Incidence Microphone

Freq range: 3.15 Hz to 12.5Hz
Dyn range: 16 dB(A) to 148 dB
Sensitivity: 50 mV/Pa
  • 40AQ 1/2

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 suitable for general purpose acoustic measurements such as diffuse fields or inside vehicles. It is perfect for environments with hard surfaces or multiple sound sources.

40AQ is included in the G.R.A.S. 46AQ Random-incidence microphone set. 

Compatibility

The 40AQ requires a standardized ½” or ¼” CCP preamplifier and an input module that supports this technology with a BNC, SMB, or Microdot connector.

For more information, see System Setup.

System verification

For daily verification and check of your measurement setup, we recommend using a calibrator like G.R.A.S. Sound Level Calibrator 42AB. 

For proper sensitivity calibration, we recommend using a pistonphone like G.R.A.S. Intelligent Pistonphone 42AP.

Quality and warranty

All G.R.A.S. microphones are made of high-quality materials that will ensure life-long stability and robustness. The microphones are all assembled in verified clean-room environments by skilled and dedicated operators with many years of expertise in this field.

The microphone diaphragm, body, and improved protection grid are made of high-grade stainless steel, which makes the microphone resistant to physical damage, as well as corrosion caused by aggressive air or gasses.

This, combined with the reinforced gold-plated microphone terminal which guarantees a highly reliable connection, enables G.R.A.S. to offer 5 years warranty against defective materials and workmanship.

Learn more about G.R.A.S.’ unique warranty policies. 

Service

If you accidentally damage the diaphragm on a G.R.A.S. microphone, we can—in most cases—replace it at a very reasonable cost and with a short turn-around time. This not only protects your investment, but also pleases your quality assurance department because you don’t have to worry about new serial numbers, etc.

Learn more about G.R.A.S.’ service program. 

Calibration

Before leaving the factory, all G.R.A.S. microphones are calibrated in a controlled laboratory environment using traceable calibration equipment.

Depending on the use, measurement environment, and internal quality control programs, we recommend recalibrating the microphone at least once a year.

Learn more about G.R.A.S.’ calibration services.

TYPE (Microphone features) RI
Frequency range (±1 dB) Hz 12.5 to 8 k
Frequency range (±2 dB) Hz 3.15 to 12.5
Frequency range (±3 dB) Hz 3.15 to 16 k
Dynamic range lower limit (microphone thermal noise) dB(A) 16
Dynamic range lower limit with G.R.A.S. preamplifier dB(A) 18
Dynamic range upper limit dB 148
Dynamic range upper limit with G.R.A.S. preamplifier @ +28 V / ±14 V power supply dB 142
Dynamic range upper limit with G.R.A.S. preamplifier @ +120 V / ±60 V power supply dB 148
Dynamic range upper limit with G.R.A.S. CCP preamplifier dB 138
Open-circuit sensitivity @ 250 Hz (±2 dB) mV/Pa 50
Open-circuit sensitivity @ 250 Hz (±2 dB) dB re 1V/Pa -26
Resonance frequency kHz 14
Microphone cartridge capacitance, typ. pF 13
Microphone venting Rear
IEC 61094-4 Compliance WS2P/D
Temperature range, operation °C / °F -40 to 120 / -40 to 248
Temperature range, storage °C / °F -40 to 85 / -40 to 185
Temperature coefficient @250 Hz dB/°C / dB/°F -0.01 / -0.006
Static pressure coefficient @250 Hz dB/kPa -0,011
Humidity range non condensing % RH 0 to 100
Humidity coefficient @250 Hz dB/% RH -0,001
Influence of axial vibration @1 m/s² dB re 20 µPa 62
CE/RoHS compliant/WEEE registered Yes / Yes, Yes
Weight g / oz 6.5 / 0.229

Typical frequency response. Upper curve shows response in a diffuse sound field (random incidence), lower curve shows pressure response.