Product Overview
The G.R.A.S. ½-inch Prepolarized Pressure Microphone Type 40AD is designed for precision acoustic measurements in various environments such as couplers, boundaries, and enclosures. It is a prepolarized pressure microphone known for its large dynamic range and wide frequency response.

Specifications

• Frequency Response: 3.15 Hz - 10 kHz (± 2.0 dB), 12.5 Hz - 7.5 kHz (± 1.0 dB)
• Nominal Sensitivity: 50 mV/Pa at 250 Hz
• Polarization Voltage: 0 V
• Dynamic Range: Upper limit at 146 dB re. 20 µPa (3% distortion), Lower limit at 16 dB re. 20 µPa (thermal noise)
• Capacitance: 20 pF
• Temperature Range: –40 °C to +120 °C
• Dimensions: Length 16.2 mm, Diameter 13.2 mm (with protection grid)
• Weight: 9 gm
• Humidity Range: 0 - 100% (non-condensing)

Design and Materials
The microphone is constructed from non-corrosive, stainless materials to withstand rough handling and corrosive environments. It is guaranteed for 5 years and comes with an individual calibration chart.

Applications
Typical applications include precision acoustic measurements, coupler measurements, and flush (boundary) measurements. It is compatible with G.R.A.S. CCP 1 preamplifiers.

Compliance and Standards
All G.R.A.S. microphones comply with IEC 1094 standards for measurement microphones, ensuring high-quality performance.

Figures and Corrections
Figures included in the document illustrate the typical frequency response and free-field corrections for various angles of incidence, highlighting the microphone's performance in different sound fields.