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40AQ 1/2" Prepolarized Random Incidence Microphone
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40AQ 1/2" Prepolarized Random Incidence Microphone
The 40AQ is an IEC 61094 WS2P/D ½" prepolarized random-incidence microphone with rear-venting. 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.
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.
Key Specifications
| Polarization/Connection | 0 V / CCP |
| Frequency range (±1 dB) | 12.5 Hz to 8 kHz |
| Frequency range (±2 dB) | 3.15 Hz to 12.5 kHz |
| Frequency range (±3 dB) | 3.15 Hz to 16 kHz |
| Dynamic range lower limit (microphone thermal noise) | 16 dB(A) |
| Dynamic range lower limit with GRAS preamplifier | 18 dB(A) |
| Dynamic range upper limit | 148 dB |
| Dynamic range upper limit with GRAS preamplifier @ +28 V / ±14 V power supply | 142 dB |
| Dynamic range upper limit with GRAS preamplifier @ +120 V / ±60 V power supply | 148 dB |
| Dynamic range upper limit with GRAS preamplifier | 138 dB |
| Open-circuit sensitivity @ 250 Hz (±2 dB) | 50 mV/Pa |
| Open-circuit sensitivity @ 250 Hz (±2 dB) | -26 dB re 1V/Pa |
| Resonance frequency | 14 kHz |
| Microphone cartridge capacitance, typ. | 13 pF |
| Microphone venting | Rear |
| Temperature range, operation | -40 to 120 °C / -40 to 248 °F |
| IEC 61094-4 Designation | WS2D |
| Temperature range, storage | -40 to 85 °C / -40 to 185 °F |
| Temperature coefficient @250 Hz | -0.01 dB/°C / -0.006 dB/°F |
| Humidity range non condensing | 0 to 90 % RH |
| Static pressure coefficient @250 Hz | -0,011 dB/kPa |
| Humidity coefficient @250 Hz | -0,001 dB/% RH |
| Influence of axial vibration @1 m/s² | 62 dB re 20 µPa |
| Weight | 6.5 g / 0.229 oz |
Specifications from the official GRAS product sheet. Please refer to the attached datasheet for full details.
