Product Overview
The G.R.A.S. 1-inch Laboratory Standard Pressure Microphone Type 40EU is designed for use in couplers and serves as a replacement for WE 640 microphones. It features a flat pressure-frequency response across its working frequency range and is compatible with G.R.A.S. 1/2-inch preamplifiers using available adapters.

Specifications

• Frequency Response: 2.6 Hz - 8 kHz (± 2.0 dB), 4 Hz - 5 kHz (± 1.0 dB)
• Nominal Sensitivity: 50 mV/Pa, –26 dB re. 1 V/Pa
• Venting: Rear vented
• Polarization Voltage: 200 V
• Dynamic Range: Upper limit of 146 dB re. 20 µPa with 3% distortion
• Thermal Noise: 9.6 dBA re. 20 µPa
• Nominal Capacitance: 56 pF
• Temperature Range: -40 °C to +150 °C
• Dimensions: Length 19.0 mm (with grid), Diameter 23.77 mm
• Weight: 32 g
• Temperature Coefficient: 0.003 dB/°C from –10 °C to +50 °C
• Static-pressure Coefficient: –0.016 dB/kPa at 250 Hz, 25 °C
• Humidity Range: 0 - 100% (non-condensing)
• Influence of Humidity: < 0.1 dB (0 - 100% RH)
• Influence of Axial Vibration: 67 dB re. 20 µPa
• IEC 61094-2 Type Designation: LS1P

Materials and Durability
The microphone is constructed from non-corrosive stainless materials, ensuring robustness and resistance to corrosive environments. It is a linear reversible transducer suitable for precision reciprocity calibrations and is guaranteed for 5 years.

Applications

• LS1P Reference Microphone
• Precision Reciprocity Calibrations
• Laboratory Reference for Secondary Calibration of Working-standard Microphones

Additional Information
Each microphone is individually checked and calibrated before leaving the factory, with a calibration chart provided. A protective dust cap is included for when the microphone is not in use.