Microphone & PreAmplifier Combinations

Type 4948B  Aerospace Surface Microphone With 2 Coaxial Cables And CIC

Type 4948B Aerospace Surface Microphone With 2 Coaxial Cables And CIC

Type 4948-B is deesigned for use on airplane surfaces during in-flight testing and is suitable for wind-tunnel testing and other similar applications.


  • Measurement of sound pressure on surfaces
  • Acoustic-fatigue testing of airplanes
  • Wind-tunnel measurements
  • Medium- to high-level measurements
  • Measurement in confined spaces

The microphone housing and the metallic parts of the diaphragm-backplate arrangement are all titanium, ensuring uniquely high resistance to corrosion.

Surface Microphone Type 4948 has a built-in preamplifier for connection to CCLD inputs. The microphone sensitivity is adjusted so as to allow measurements at high levels without clipping. All versions of Type 4948 support TEDS (Transducer Electronic Data Sheet). TEDS enables remote transducer identification and reading of calibration data. Type 4948 B also supports Brüel & Kjær’s proprietary Charge Injection Calibration (CIC) for remote verification of the complete, calibrated measurement channel.

The microphone offers high mounting flexibility and its diaphragm is flush with the microphone housing in order to minimise the microphone’s wind-generated noise. The microphone’s pressure-equalisation vent is placed just next to the diaphragm on the front of the microphone; this is important as static pressure can vary rapidly with position in the applications for which the microphone is designed.

Surface Microphone Type 4948 is the first product based on Brüel & Kjær’s new, patent-pending, microphone-manufacturing technology. With this technology, it is possible to obtain the same high stability and uniformity as those of the traditional and well-known Brüel & Kjær microphones and preamplifiers, even with Type 4948’s flat, compact design.


Capacitance: pF

Diameter: 1/2

Dynamic range: 55 – 160 dB

Frequency range: 5 – 20000 Hz

Inherent noise: 55 dB A

Lower limiting frequency -3dB: 5 Hz

Optimised: Surface

Polarization: Prepolarized

Polarization voltages: V

Pressure coefficient: -0.007 dB/kPa

Sensitivity: 1.4 mV/Pa

Temperature coefficient: 0.013 db/ºC

Temperature range: -55 – 100 C

Venting: Front

Weight: gram

Sound field: Special

Input type: CCLD IEPE

Microphone type: Surface