TYPE 4939

¼-inch free-field microphone, 4 Hz to 100 kHz, 200V polarization

Designed for high-level and high-frequency measurements.

Demande de devis

Free-field ¼" microphone Type 4939 is specially designed for high-level and high-frequency measurements. By using stainless steel diaphragm and protection grid, the microphone is optimised to withstand rough environments and is capable of working at high temperatures up to 150°C (302°F).

USE SCENARIOS

  • High level measurements
  • High frequency measurements
  • Model work

ROBUSTNESS

The microphone is capable of withstanding the IEC 68-2-32 1 metre drop test.

CALIBRATION

The sensitivity can be calibrated at 250 Hz by using Pistonphone Type 4228 with ¼" Adaptor DP 0775. The actuator response can be measured using Actuator UA 0033 with Adaptor DB 0264. The free-field response can be obtained by adding the type-specific, free-field correction to the actuator response.

Capacitance
6.1 pF
Diameter
1/4
Dynamic range
28 – 164 dB
Frequency range
4 – 100000 Hz
Inherent noise
28 dB A
Lower limiting frequency -3dB
3 Hz
Optimised
Free field
Polarization
Ext polarized
Polarization voltages
200 V
Pressure coefficient
-0.007 dB/kPa
Sensitivity
4 mV/Pa
Standards
IEC 61094-4 WS3F
Temperature coefficient
0.003 db/ºC
Temperature range
-40 – 150 C
Venting
Side
Weight
gram
Sound field
Free-field
Input type
Classic
Microphone type
Free field