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Sound and Vibration Instrument Hire and Calibration

Bruel & Kjaer 4226 Specifications


 
Bruel & Kjaer 4226 Acoustic Calibrator
 
B&K 4226 Acoustic Calibrator - Class 1 - multi-function n/a
 

Not available for hire, details retained for information purposes only.

Complies with IEC 942 Sound Calibrators, Class 1


at Reference Sound Pressure Level
at Reference Ambient Conditions
94 dB SPL ± 0.2 dB re 20 µPa, at 1 kHz
 

Nominal Sound Pressure Levels :

94 dB SPL, 104 dB SPL and 114 dB SPL
 

10 dB and 20 dB Level Step Accuracy :

± 0.1 dB for f < 8 kHz;   ± 0.2 dB for f > 8 kHz
 

Nominal Frequencies :

from 31.5 Hz to 16 kHz in octave steps, plus 12.5 kHz
 

Frequency Accuracy :

± 1 % re the BS ISO 266 stated exact frequencies
 

Frequency Stability :

better than ± 30 ppm
 

Reference Ambient Conditions :


Ambient Temperature : 20 °C
Ambient Pressure : 1013 hPa
 

Influence of Ambient Conditions :

at Reference Sound Pressure Level
Ambient Temperature : +0.002 dB/°C in the range -10 °C to +50 °C, max. temp. uncertainty ± 5 °C
Ambient Pressure : +0.00055 dB/hPa in the range 650 hPa to 1080 hPa, max. pressure uncertainty ± 30 hPa to satisfy class 1 requirements
Magnetic Field Sensitivity : no observable effect < 0.01 dB at 100 A/m
 

Frequency Response :


Pressure Field : Linear 94 dB, 104 dB and 114 dB SPL and inverse A-weighting, 94 dB SPL at 1 kHz
Equivalent 0 ° Free and Random Field : Linear 94 dB SPL and inverse A-weighting, 94 dB SPL at 1 kHz
 

Level Accuracy at Fixed Frequencies :

Lin and inverse A-weighting
 

Pressure Field Response - re 1 kHz

31.5 Hz - 125 Hz ± 0.15 dB    
250 Hz - 500 Hz ± 0.10 dB
2 kHz - 4 kHz ± 0.15 dB
8 kHz ± 0.25 dB
12.5 kHz - 16 kHz     ± 0.50 dB
 

Equivalent 0 ° Free and Random Field Response : re 1 kHz

31.5 Hz - 125 Hz     ± 0.20 dB    
250 Hz - 500 Hz ± 0.10 dB
2 kHz ± 0.20 dB
4 kHz ± 0.30 dB
8 kHz ± 0.50 dB
12.5 kHz ± 1.00 dB
16 kHz ± 1.50 dB
 

Total Harmonic Distortion :

< 1 %
 

Additional Functions :


Time Weighting Tests :
Frequency : 2 kHz pre-selected
Test Level : Typically 94 dB SPL, adjustable ± 12 dB approximately
Signal : Continuous reference and tone burst
Level between Bursts : Ref. level -20 dB
Burst Duration : 500 ms Slow and 200 ms Fast
 

Crest Factor Test :


Frequency : 2 kHz pre-selected
Test Level : typically 94 dB SPL, adjustable ± 12 dB approximately
Signal : continuous reference and tone burst of 40 Hz repetition frequency. Crest Factor 3 at pre-selected and higher frequencies

Note :

All burst signals consist of an integral number of sine waves with amplitude shifting at zero crossing
 

Dose Meter Calibration :


Calibration Period : 30 s : Obtained doses at 1 kHz:
SPLIECANSI
  94 dB SPL     0.26 %   ± 0.01 %     0.18 %   ± 0.01 %   
104 dB SPL2.64 %   ± 0.02 % 0.73 %   ± 0.03 %
114 dB SPL26.7 %   ± 0.02 % 2.90 %   ± 0.12 %
 

AC Output :


Output Voltage : 12.5 mV ± 0.5 mV at settings 94 dB, 1 kHz and pressure mode.
Voltage changes according to the selected level, type of microphone , sound field and function. Signal for testing time weighting and crest factor capabilities as above, except that the crest factor is 10

Note:

The acoustic output signal is switched off when a plug is inserted in the AC OUT socket
 

Output Impedance :

600 Ω short circuit proof
Frequency Response : ± 0.2 dB from 31.5 Hz to 16 kHz in pressure mode
Note : The acoustic output is switched off when a plug is inserted in the AC OUT socket
 

External Generator Input :


Input Voltage : 0.5 V to 1.5 V
Input Impedance : 47 kΩ
 

Frequency Response in the Coupler :

31.5 Hz - < 8 kHz     ± 0.15 dB    
8 kHz - < 12.5 kHz ± 0.25 dB
12.5 kHz - 16 kHz ± 0.50 dB
 

Note:

These tolerances are relative to the inverse pressure response of the reference microphone. Only Pressure and Linear response are possible with external generator.
 

Stabilization Time:

The LED corresponding to the selected frequency lights continuously when the SPL is stabilized, typically 2 to 10 seconds
 

Power Supply :


Batteries : 4 x Lr6 - 1.5 V alkaline
Battery Life : 10 hours approximately at 20 °C with alkaline batteries
Battery Check : The 'Batt Low' LED is lit when reaching the last 10 % of the battery life
 

Effective Coupler Volume :

Approximately 400 cm3 at 31.5 Hz, decreasing to approximately 30 cm3 at 1 kHz, obtained by feedback
 

Environmental :


Ambient Temperature : -10 °C to +50 °C
Ambient Pressure : 650 hPa to 1080 hPa
Ambient Humidity : 5 % to 90 %RH
 

Dimensions and Weight :

including mahogany case
Length : 265 mm
Width : 125 mm
Height : 62 mm
Weight : 1.5 kg
 
E&OE - specifications subject to change without notice.