Tristate Machinery Dismantlers Forum   >   STATE OF IOWA   >   Industrial Machines   >   New   >   Bruel & kjaer b&k 4189 ½" microphone capsule - tested

Bruel & kjaer b&k 4189 ½" microphone capsule - tested


This is a current product from B&K and the product datasheet can be found here (although B&K now requires registration for their datasheet downloads this is free):
http:// /doc/bp2210.pdf
This is one of B&K's finest standard (as in reference) microphones with legendary stability and accuracy. The following is an extract from the product datasheet:
Type 4189 is designed for high-precision, free-field measurements where a microphone with high sensitivity is required. Being prepolarized, Type 4189 can be used with both DeltaTron and classical preamplifiers.
* Precision sound measurement
* Premium class sound level meters
* Equipment complying with IEC 61672 class 1
* Dynamic Range: 14.6 - 146 dB
* Temperature: -30 to +150 C (-22 to +302 F)
* Polarization: Prepolarized
* Use of Free-field Microphones
At higher frequencies, reflections and diffractions causes a pressure increase in front of the diaphragm of a microphone. If not corrected, for this would result in an increased output voltage. A free-field optimisation means that the frequency response of the microphone has been designed in such a way that the free-field response at 0 degrees incidence is flat. This microphone is optimised for use with the protection grid in place.
Free-field microphones are commonly used for sound measurement in an anechoic chamber or far away from reflecting buildings, etc. Another area for free-field microphones is for general electroacoustic measurements purposes like loudspeaker and microphone measurements.
Type 4189 is suited for use in class 1 Sound Level Meters and for all high-precision acoustic measurements where a robust and stable free-field microphone with an upper frequency of 20 kHz is required.
A press-fitted, stainless-steel diaphragm ensures superior long-term stability and mechanical robustness - Type 4189 will withstand the 1m drop test of IEC60068-2-32. All Br el&Kj r Measuring Microphones are assembled in a clean room. This ensures that the microphones maintain their inherent low noise floor and high stability, even when used in environments with a combination of high humidity and high temperature.
Being prepolarized, Type 4189 is especially well suited for battery operated equipment and operation in environments with high humidity.
* IEC 61094-4 Type Designation: WS2F
* Polarization Voltage: 0V (prepolarized)
* Open-circuit Sensitivity (250 Hz): 50mV/Pa, 26 dB 1.5 dB re 1 V/Pa
* 0 Incidence Free-field Response: 10 Hz to 8 kHz: 1dB, 6.3Hz to 20 kHz 2 dB
* Lower Limiting Frequency ( 3dB): 2 to 4Hz
* Pressure Equalization Vent: Rear vented
* Diaphragm Resonance Frequency: 14 kHz (90 phase shift)
* Cartridge Capacitance: 14 pF at 250 Hz
* Equivalent Air Volume: 46mm3 (250 Hz)
* Pistonphone Correction (Type 4228 with DP-0776) 0.00 dB
* Cartridge Thermal Noise: 14.6 dB(A), 15.3 dB(Lin)
* Upper Limit of Dynamic Range (3% Distortion): >146 dB SPL
* Max. Sound Pressure Level: 158 dB (peak)
* Operating Temperature Range: 30 to +150 C ( 22 to +302 F)
* Storage Temperature: 30 to +70 C ( 22 to +158 F)
* Temperature Coefficient (250 Hz): -0.006 dB/K ( 10 to +50 C, 14 to 122 F)
* Pressure Coefficient: 0.01 dB/kPa
* Operating Humidity Range: 0 to 100% RH (without condensation)
* Influence of Humidity: <0.1 dB in the absence of condensation
* Vibration Sensitivity (<1000 Hz): 62.5 dB equivalent SPL for 1m/s2 axial vibration
* Magnetic Field Sensitivity: 6 dB SPL for 80 A/m, 50 Hz field
* Estimated Long-term Stability: >1000 years/dB in dry air at 20 C (68 F), >2 hours/dB in dry air at 150 C (302 F)), >40 years/dB in air at 20 C (68 F), 90% RH)
_________________________________________________________________________________________________
I took the screen off to look at the diaphragm. The marks you can see are just dust.
It looks in perfect condition and I mounted it on one of my 2669 pre-amplifiers and it calibrated pretty close on my 94dB calibrator based on the nominal calibration value. A tribute to B&K's legendary product quality.
There is no guarantee with the item but I do warrant against DOA and performance indicated by testing.



Bruel & kjaer b&k 4189 ½