Product Overview
The G.R.A.S. 1⁄2-inch Laboratory Standard Pressure Microphone Type 40AU is designed for precise sound pressure measurements in various applications such as couplers, ear simulators, and laboratory reference measurements. It features a large dynamic range and an extended frequency response, making it suitable for high-frequency calibrations.

Specifications

• Frequency Response: 3.15 Hz to 20 kHz (±1.5 dB), 5 Hz to 12.5 kHz (±1.0 dB)
• Nominal Sensitivity: 12.5 mV/Pa
• Polarization Voltage: 200 V
• Dynamic Range: Up to 160 dB re. 20 µPa with 3% distortion
• Microphone Thermal Noise: 20 dBA re. 20 µPa
• Capacitance: 20 pF
• Temperature Range: -40 °C to +150 °C
• Dimensions: Length 12.0 mm, Diameter (front) 13.2 mm, Diameter (back) 12.7 mm
• Weight: 7 g
• Humidity Range: 0 - 100% (non-condensing)

Design and Compliance
The microphone is made from non-corrosive stainless materials to withstand harsh environments. It complies with IEC 61094 standards for laboratory microphones and is compatible with various G.R.A.S. preamplifiers.

Performance and Calibration
The Type 40AU has a flat pressure-frequency response and requires corrections for reflections and diffractions in open sound fields. Each microphone is individually calibrated, and a calibration chart is provided.

Applications
Typical uses include LS2aP reference microphone applications, precision sound pressure measurements, and laboratory reference measurements.