¼-inch Free-fi eld Microphone Type 40BF

Product catalog summary

Product Overview: The G.R.A.S. Microphone Type 40BF is a ¼-inch precision condenser microphone designed for general-purpose measurements in open acoustic fields. It is an externally polarized free-field microphone with a large dynamic range and wide frequency response, suitable for measuring sound pressure levels before its placement in the sound field.

Specifications:

Frequency Response: 4 Hz - 100 kHz (± 2.0 dB), 10 Hz - 40 kHz (± 1.0 dB)
Nominal Sensitivity: 4 mV/Pa
Polarization Voltage: 200 V
Upper Limit (3% Distortion): 166 dB re. 20 µPa
Microphone Thermal Noise: 30 dBA re. 20 µPa
Capacitance: 7 pF
Temperature Range: -40 °C to +150 °C
Dimensions: Length/Diameter with protection grid: 10.5 mm/6.9 mm; without protection grid: 9.1 mm/6.3 mm
Weight: 1.75 g

Compliance and Durability: The microphone complies with IEC 1094 standards for measurement microphones and is made from non-corrosive, stainless materials to withstand rough handling and corrosive environments. Each microphone is guaranteed for 5 years and comes with an individual calibration chart.

Applications: Suitable for sound pressure measurements, high-frequency measurements, high-level measurements, and acoustic transient measurements.

Additional Features: The microphone is compatible with G.R.A.S. ¼-inch preamplifiers and other similar preamplifiers. It features rear venting, which is advantageous for critical phase response applications.

Figures:

Figure 1: Shows the true size of the ¼-inch Free-field Microphone Type 40BF.
Figure 2: Illustrates the typical frequency response of Type 40BF without the protection grid.
Figure 3: Displays free-field corrections for various angles of incidence without the protection grid.

¼-inch Free-fi eld Microphone Type 40BF

¼-inch Free-fi eld Microphone Type 40BF

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