Product Overview
The G.R.A.S. Microphone Type 40DD is a ⅛-inch pressure microphone designed for high-frequency and high-level sound measurements. Its small size minimizes diffraction and reflection effects, making it suitable for precise sound field measurements.

Specifications

• Sensitivity: 0.7 mV/Pa at 250 Hz
• Frequency Response: 10 Hz - 30 kHz (±1.0 dB), 6.5 Hz - 80 kHz (±2.0 dB), 6.5 Hz - 140 kHz (±3.0 dB)
• Dynamic Range: Upper limit at 174 dB re. 20 µPa (3% distortion), Lower limit at 40 dBA re. 20 µPa (thermal noise)
• Polarization Voltage: 0 V
• Resonant Frequency: 160 kHz (90° phase shift)
• Dimensions: Length 6.7 mm, Diameter 3.5 mm (with protection grid)
• Weight: 1.5 g
• Temperature Range: -40 °C to +120 °C

Materials and Durability
The microphone is constructed from non-corrosive stainless materials, ensuring durability in harsh environments. Each unit is individually calibrated and comes with a 5-year guarantee.

Applications
Ideal for sound-pressure, high-frequency, very high-level pressure, and impulse-noise measurements.

Additional Information
The microphone requires an adapter (RA0063 or RA0082) for mounting onto ¼-inch preamplifiers. Compatible preamplifiers include G.R.A.S. Types 26CC and 26CB.