Manufacturers' Specifications

Bruel & Kjaer 2236

Precision Sound Level Meter
Conforms with IEC 60651 and 60804 Type 1

Measuring Ranges :

Note * : Level non-linearity caused by noise floor is < 0.4 dB at 30 dBA, re IEC 651 and < 1 dB at 26 dBA
Note 1 : with crest factor = 10 or 20 dB

Noise Floor :
Typically 18 dBA
Maximum : 20 dBA RMS
Includes preamplifier's electrical noise and microphone's thermal noise

Detectors : simultaneous RMS and Peak with independent frequency weightings
Linearity Range : 80 dB
Pulse Range :  83 dB
Non-linear Distortion : too small to affect accuracy
Peak Detector Rise Time : < 50 ms

Frequency Weightings : selected independently for RMS and Peak
RMS A and C : according to IEC 651 Type 1
RMS L : flat from 10 Hz to 20 kHz ± 2 dB with Type 1 tolerances
Peak C : according to IEC 651 Type 1
Peak L : flat from 10 Hz to 20 kHz ± 2 dB with Type 1 tolerances

Time Weightings : Fast, Slow, Impulse, according to IEC 651 Type 1

Display : 4 line LCD showing:
Measuring range and quasi-analogue bar showing input signal
Battery low, pause and overload with hold indicators
Time weighting and elapsed measurement time
Optional back light
The quasi-analogue bar is updated 15 times per second
Displayed parameter level updated once per second

Parameters :
MaxL,  MinL,  MaxP,  Peak,  SPL,  Leq,  SEL,  LEP,d and Overload in % of measurement time + variable Ln, default values L90,  L50 and  L10

Exchange Rate : 3

Resolution :
LN Values : 0.5 dB
Other Parameters : 0.1 dB

Reset :
Resets Buffer including elapsed time to zero. Warning prior to reset if elapsed time > 1 min.
Reset when changing frequency or time weighting
Resets all results in Log, Memory and Buffer if held down together with (Data)
Optional reset when changing level of measurement range, Lns not available if range change is without reset

Microphone : Type 4188 pre polarized free-field 1/2" condenser microphone
Sensitivity : -30 dB re 1 V/Pa ± 2 dB
Frequency Range : 8 Hz to 12.5 kHz ± 2 dB
Capacitance : 12 pF

Memory : 40 Records of Overall Results
Result Logging : Leq : L10 and L90
Log Rate : 1 s : 10 s : 30 s : 1 m : 5 m : 10 m : 15 m : 30 m and 60 m.
Memory Capacity : 512 Kbytes, equivalent to 86400 sets of results (for example, 24 hours of 1 s logging)

Serial Interface : Compatible with EIA-574
Baud Rate : 1200 - 19200
Data Bits : 8
Stop Bit : 1
Parity : none
Handshake : Hardwired, XON / XOFF or None

Results Output Format :
Overall : Logged 2318 printer : Logged spreadsheet : Level Distribution : Cumulative Distribution : Distribution resolution 1 to 5 dB

Heading : long or short

DC Output : Short circuit protected coaxial Lemo socket (series 00)
Output : 50 mV/dB equivalent to 0 - 4.15 V
Output Resistance : 100 Ω
Output Parameter : same as the Displayed Parameter

AC Output : Short circuit protected coaxial Lemo socket (series 00)
Maximum Output : 0.5 V RMS corresponding to the top of the selected measurement range ± 2 dB depending on the microphone's sensitivity
Output Resistance : 100 Ω
Output : output signal from preamplifier (L frequency weighting)

Clock : real time, calendar and measurement duration

Warm up Time : < 5 s

Settling Time : at range change without reset: < 4 ms

Calibration Conditions :
Reference Frequency : 1000 Hz
Reference SPL : 94 dB
Reference Range : 50 - 130 dB, set automatically during calibration sequence
Reference Incidence : Frontal

Environmental :
Storage Temperature : -25 to +70 ° C
Operating Temperature : -10 to +50 °C
Effect of Temperature : < 0.5 dB, -10 to +50 °C
Effect of Humidity : < 0.5 dB for 30 %RH at 40 °C and 1 kHz
Vibration Sensitivity : < 80 dB with L-weighting at 1 m/s^-2
Magnetic Field : 80 A/m, 1Ørsted at 50 Hz gives < 34 dBL

Power Supply - Internal :
Batteries :   4 x 1.5 V LR6 / AA size alkaline cells
Battery Life : > 12 hours, typically
Back up battery : keeps clock and memories operating for at least 6 months, if fully charged

External Power Supply:
Voltage : 7 - 15 V DC regulated
Voltage Ripple : < 100 mV peak to peak
Maximum Current : 400 mA
Average Current : 100 mA at 7 V

External Power Supply Socket :
Socket Pin: Positive
Socket Casing : Signal Ground
Socket Pin Diameter : 2.0 mm
Socket External Diameter : 5.5 mm

Dimensions and Weight :
Size : 257 mm x 97 mm x 41 mm
Weight : 460 g including batteries