Sound and Vibration Instrument Hire and Calibration

Bruel & Kjaer 4226 Specifications

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:

SPL	IEC	ANSI
94 dB SPL	0.26 %   ± 0.01 %	0.18 %   ± 0.01 %
104 dB SPL	2.64 %   ± 0.02 %	0.73 %   ± 0.03 %
114 dB SPL	26.7 %   ± 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.
* Our standard hire charges are based on a 4-day minimum period, details other options.