TYPE 4947

1/2" Pressure-field Microphone, Prepolarized, 8 Hz - 10 kHz

Pressure-field microphone designed for coupler measurements in connection with telephone and hearing aid testing over a frequency range of 8 Hz To 10 kHz.

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Prepolarized 1/2-inch Microphone Type 4947 is optimised for pressure-field measurements such as coupler measurements, close to hard reflective surfaces, in enclosures or cavities that are small compared to the wavelength.

For example, in connection with telephone and hearing aid testing. The microphone is prepolarized, which enables connection to CCLD input conditioning. The microphone is capable of withstanding the IEC 68-2-32 1 meter drop test.

USE SCENARIOS

  • Coupler measurements
  • Hearing aid testing
  • Telephone testing
  • Connect to CCLD input
  • High-humidity environments

CALIBRATION

The sensitivity can be calibrated at 250 Hz by using Pistonphone Type 4228 with ½" inch Adaptor DP 0776. The actuator response can be measured using Electrostatic Actuator UA 0033.

The pressure-field response can be obtained by adding the relevant correction curve to the actuator response.

Capacitance
14 pF
Diameter
1/2
Dynamic range
17.5 – 160 dB
Frequency range
8 – 10000 Hz
Inherent noise
17.5 dB A
Lower limiting frequency -3dB
5 Hz
Optimised
Pressure Field
Polarization
Prepolarized
Polarization voltages
V
Pressure coefficient
-0.006 dB/kPa
Sensitivity
12.5 mV/Pa
Temperature coefficient
0.006 db/ºC
Temperature range
-30 – 125 C
Venting
Rear
Weight
gram
Sound field
Pressure-field
Microphone type
Pressure Field