BRUEL & KJAER 2221 - Technical Specifications

Calibration
Calibration is easily carried out
using Sound Level Calibrator Type
4230, which fits directly over the mi-
crophone and produces a nominal
sound pressure level of 94 dB ( ± 0,3
dB). Calibration with the Type 4230
permits a check of the entire instru-
ment, including the microphone.
AC Output
An AC output provides the ampli-
fied and filtered signal. Upper range
limit corresponds to 2 V RMS. It is
dB
80
60
40
50 100
200 500
kHz 2
87 7314
50
100
200
500 1 kHz 2
871375
Fig.6. Equivalent Sound pressure level when complete Sound Level Meter is excited vertically
and horizontally at 1 ms·
2
well suited for level recording, par-
ticularly with the Portable Level Re-
corder Type 2306 which is also bat-
tery powered.
Specifications 2221 and 2222
Measuring Range:
Leq
Max. Hold Max. Hold "Peak"
dB( A)
" Fast/Slow" dB(A) dB(Lin.)
25-85
40-85 55-88
45-105
60-105 60-108
65-125
80-125 80-128
85-145
100-145 100-148
Signal to noise ratio > 5 dB at 25 dB(A)
Frequency Response:
See Figs.3 and 4
Frequency Weighting:
In "Leq", "SEL" and Max . Hold "Fast/
Slow ": A-weighting to IEC 651 Type 1
In Max. Hold "Peak": Linear (20 Hz -
20 kHz, +0,5 dB -3 dB) *
Detector:
Characteristics: true logarithmic RMS
Linearity range: 60 dB
Pulse range: 63 dB
Crest factor capability: 1.4 at upper limit
of measuring range increasing linearly
with decreasing signal to a maximum of
50 for Max. Hold " Fast/Slow" . For Leq .
overload is the only crest factor limitation
(63 dB)
Time Weighting Characteristics:
"Fast" (2221 ): to IEC 651 Type 1 *
"Slow" (2222): to IEC 651 Type 1 *
"Peak": rise time < 30 1-1s
Max. Hold decay rate: < 0,05 dB/s
Leq Response Time for Constant Input
Signal:
~
First Final Final
read ing reading reading
I
± 0,5 dB ± 0,1 dB
At bottom of range 4s
32 s 174s
10 dB above bottom
1 s 3,5 s
17,5 s
of range
20 dB or more above
bottom of range
1 s 1 s
4,5 s
• The modifications proposed (see p. 2 & 3) can be
carried out by your local B & K representative .
Maximum Measurement Period:
Leq: 2,77 hours (for periods longer than
2,77 hours Leq can be determined from
the SEL)
SEL: only limited by battery life
Display:
31 12 digits 7 segments, liquid crystal ,
7,2 mm high
Leq. SEL: resolution 0,1 dB updated twice
per second
Max. "Fast/Slow", Max. "Peak": resolu-
tion 0,1 dB updated once per second , dis-
play response time less than 3 seconds
Additional functions:
Overload indicated by : &
Underrange indicated by: T
Battery low indicated by : BAT
Overflow of time counter indicated by : *
Weighting curve indicated by : A or L
AC Output:
2 V RMS for full scale, output impedance
1 krl, short circuit protected
Reset Function:
Reset occurs when " Reset " is pressed or
when changing " Leq Range " or " Function "
(except between L eq and SEL)
Microphone:
Type: 1 12 inch B & K Prepolarized Con-
denser Microphone Type 4176
Sensitivity: 50 mV /Pa
Capacitance: 13 pF
Windscreen effect: < 0,5 dB up to 10 kHz
Calibration:
Screwdriver operated potentiometer ad-
justment using Sound Level Calibrator
Type 4230
Reference Conditions for Calibration
Validity:
Type of Sound Field: Free
Reference Incidence Direction: Perpen-
dicular to microphone diaphragm
Reference SPL: 94 dB (re 20 1-1Pa)
Reference Frequency: 1 kHz
Reference Temperature: 20° C
Reference Measuring Range:
45 - 105 dB( A)
Warm-up Time:
< 1 s
Effect of Humidity (at 40°C and 1000 Hz):
< 0,5 dB for 30%< RH < 90%
Effect of Temperature:
Microphone: -0 ,004 dB / ° C typically
Complete instrument:
- 0,004 ± 0,016 dB / ° C
Storage temperature: 70° C (158° F) max .
(dry air) . 100 hours max. at 40°C (104° F)
and 90% RH
Effect of Magnetic Field:
80 A/ m (1 0rsted) at 50 Hz gives :
<
25 dB (A) or < 55 dB (Lin)
Vibration Sensitivity:
See Fig.6
Batteries:
Type: Three 1,5 V Alkaline cells IEC type
LR 6 (B&K order No. QB 0013)
Life: approx . 10 hours
Overall Dimensions and Weight:
205 X 72 X 24 mm (8 X 2,8 X 0,95 in)
400 g (0,86 lb) with batteries
Accessories Included:
Half inch Prepolarized Con-
denser Microphone .................... Type 4176
Random Incidence Adaptor .......... DZ 9566
Leather Carrying Case ................. KE 0208
2,5 mm mini-jack plug .................. ... JP 0213
Windscreen .............................. .. .... .. UA 0459
Cells (x 3) ......................................... QB 0013
Accessories Available:
Sound Level Calibrator .............. Type 4230
Level Recorder Cable .................... AO 0173
3 m Microphone Extension
cable with threaded attach-
ment (UNC 1;4" x 20) for di-
rect connection to tripod .............. AO 0185
10
m cable as above .... .. ............... AO 0186
Ordering Information:
Types 2221 and 2222 are identical except
that Type 2221 has " Fast " time weight-
ing, whilst Type 2222 has " Slow " time
weighting.