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40AD 1/2" Prepolarized Pressure Microphone, High Sensitivity
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40AD 1/2" Prepolarized Pressure Microphone, High Sensitivity
The 40AD is an IEC 61094 WS2P ½" prepolarized pressure microphone with rear-venting. The externally polarized equivalent is GRAS 40AP
GRAS 40AD a high-precision condenser microphone made according to IEC 61094-4 requirements and is ideal for coupler measurements in both laboratory and production environments. It is extremely robust and reliable and can measure sound pressure levels up to 148 dB and down to 16 dB(A) in the range of 3.15 Hz to 10 kHz. The presence of the 40AD in a sound field at low frequencies is minimal due to its small size compared to the large wavelengths.
40AD is individually factory-calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response.
Key Specifications
| Polarization/Connection | 0 V / CCP |
| Frequency range (±1 dB) | 12.5 Hz to 7.5 kHz |
| Frequency range (±2 dB) | 3.15 Hz to 10 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. | 20 pF |
| Microphone venting | Rear |
| Temperature range, operation | -40 to 120 °C / -40 to 248 °F |
| IEC 61094-4 Designation | WS2P |
| 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 | -0,014 dB/kPa |
| Humidity coefficient @250 Hz | 0,001 dB/% RH |
| Influence of axial vibration @1 m/s² | 62 dB re 20 µPa |
| Weight | 9 g / 0,317 oz |
Specifications from the official GRAS product sheet. Please refer to the attached datasheet for full details.
