TYPE 4938

1/4-inch Pressure-field Microphone, Externally Polarized

Pressure-field microphone for high-level and high-frequency measurements over a frequency range of 4 Hz to 70 kHz.

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Pressure-field ¼-inch Microphone Type 4938 is designed for high-level and high-frequency measurements. The microphone is geared to withstand rough handling and high temperatures of up to 300°C (572°F).

USE SCENARIOS

  • High temperature measurements
  • High level measurements
  • High frequency measurements
  • Flush mounting

DESIGN AND ROBUSTNESS

The shape of the microphone front ensures excellent microphone performance when flush-mounted and the laser-welded diaphragm on the microphone housing ensures that the sensitivity is resistant to rough handling during flush mounting. The robustness of the microphone makes it capable of withstanding the IEC 68-2-32 1 metre drop.

CALIBRATION

The sensitivity can be calibrated at 250 Hz using Pistonphone Type 4228 with ¼-inch Adaptor DP 0775. The pressure-field response can be measured using Actuator UA 0033 with Adaptor DB 0264. The pressure-field response is equal to the actuator response.

Capacitance
6.1 pF
Diameter
1/4
Dyn. range
30 – 172 dB
Freq. range
4 – 70000 Hz
Inherent noise
30 dB A
Lower limiting frequency -3dB
3 Hz
Optimised
Pressure Field
Polarization
Ext polarized
Polarization voltages
200 V
Pressure coefficient
-0.003 dB/kPa
Sensitivity
1.6 mV/Pa
Standards
IEC 61094-4 WS3P
Temperature coefficient
0.003 dB/ºC
Temperature range
-40 – 150 ℃
Venting
Side
Weight
gram
Sound field
Pressure-field
Input type
Classic
Microphone type
Pressure Field