Bruel & Kjaer TYPE 4176
½-inch free-field microphone, 6.5 Hz to 12.5 kHz, prepolarized

Type 4176 is a prepolarized ½" Free-field Microphone designed for accurate and reliable sound measurements, as required for sound level meters in accordance with IEC 61672 class 1 and ANSI S 1.4 Type 1.

CALIBRATION
The sensitivity of Type 4176 can be calibrated at 250 Hz using Pistonphone Type 4228 with Adaptor DP 0776, or at 1 kHz using Sound Level Calibrator Type 4231. Calibration in an extended frequency range is possible using Multifunction Acoustic Calibrator Type 4226.

Specifications

Capacitance                   12.5 pF
Diameter                       1/2
Dynamic range               14 – 142 dB
Frequency range             6.5 – 12500 Hz
Inherent noise                13.5 dB A
Lower limiting frequency -3dB  5 Hz
Optimised                       Free field
Polarization                     Prepolarized
Polarization voltages        0 V
Pressure coefficient         -0.02 dB/kPa
Sensitivity                      50 mV/Pa
Temperature coefficient   -0.004 db/ºC
Temperature range          -30 – 100 C
Venting                           Rear
Weight                            gram
Sound field                      Free-field
Input type                       Classic
Microphone type               Free field