TYPE 4940

½-inch free-field microphone, 2 Hz to 20 kHz, prepolarized

Suitable for both outdoor and industrial environment measurements and for IEC 60651 Type 1 measurements and frequency analysis measurements

Request a quote

Prepolarized Free-field ½-inch Microphone Type 4940 offers significant benefits when used with portable instruments. It is particularly suitable for both outdoor and industrial environment measurements. It is also suitable for IEC 60651 Type 1 measurements and frequency analysis measurements.

USE SCENARIOS

  • Sound level meters  
  • Noise measurements according to IEC and ANSI standards
  • Transport noise measurements

FEATURES

  • Wide dynamic range from 14.6 dB(A) – 146 dB (3% distortion limit)
  • Low ambient temperature coefficient
  • IEC 60651 Type 1 approved with Modular Precision Sound Level Meter Type 2231

ROBUSTNESS

The microphone is capable of withstanding the IEC 68 232 1 metre drop test.

CALIBRATION OF SENSITIVITY AND FREQUENCY RESPONDS

The sensitivity can be calibrated at 250 Hz using Pistonphone Type 4228 with ½-inch Adaptor DP 0776. The actuator response can be measured using Actuator UA 0033. The free-field response can be obtained by adding the type-specific, free-field corrections to the actuator response.

Capacitance
14 pF
Diameter
½
Dynamic range
14.6 – 146 dB
Frequency range
6.3 – 20000 Hz
Inherent noise
14.6 dB A
Lower limiting frequency -3dB
4 Hz
Optimised
Free field
Polarization
Prepolarized
Polarization voltages
V
Pressure coefficient
-0.01 dB/kPa
Sensitivity
50 mV/Pa
Temperature coefficient
-0.001 db/ºC
Temperature range
-30 – 150 C
Venting
Rear
Weight
gram
Sound field
Free-field
Microphone type
Free field