Products

Brüel & Kjær has developed the 1” Condenser Microphone Type 4179 and Microphone Preamplifier Type 2660 system for measuring ultra-low sound pressure levels.

USE SCENARIOS

• Hearing research
• Monitoring of very low background noise levels
• Sound Power measurement of very-low-level sources
• Distanced measurement of very-low-level compressor, fan or motor noise where close measurements are impaired by wind-induced noise

High-quality, conventional 1” condenser microphones, such as B&K Types 4144 and 4145, and half-inch diameter Types 4189 and 4190, provide for the majority of noise measurements to IEC, ISO and ANSI standards. However, for measurements around the 20 μPA reference pressure, a very low noise floor in the 1/3-octave bands between 20 Hz and 20 kHz is needed.

LOW NOISE FLOOR

The microphone and preamplifier system, with a noise floor of typically -2,5dB(A), provides for this area without compomising the useful frequency range and omnidirectivity of a microphone intended for precision measurements.

With narrow-band analysis, the noise floor falls to approximately -16dB for 1/3-octave bandwidth at 1 kHz, and -34dB for 3,16Hz bandwidth at 1 kHz. The system is thus well-suited to both laboratory and industrial applications ranging from hearing research to the measurement of very-low-level machine noise.

Capacitance: 40 pF
Diameter: 1
Dynamic range: -2.5 – 102 dB
Frequency range: 10 – 10000 Hz
Inherent noise: -5.5 dB A
Lower limiting frequency -3dB: 7 Hz
Optimised: Low Noise
Polarization: Ext polarized
Polarization voltages: 200 V
Pressure coefficient: -0.016 dB/kPa
Sensitivity: 100 mV/Pa
TEDS UTID: –
Temperature coefficient: -0.004 db/ºC
Temperature range: -10 – 50 C
Venting: Side
Weight: gram
Sound field: Special
Input type: Classic
Microphone type: Low Noise