BRUEL & KJAER 2206 User manual

Instruction Manual
Precision Sound Level Meter Type 2206
033-0120
2206
Small, lightweight, Precision Sound Level
Meter fulfilling requirements of IEC 1 79 .
+ Bri.iel & Kj~r

PRECISION SOUND LEVEL METER
TYPE 2206
Revision October 1 977

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS (PRODUCT DATA) ................................................. 1
2. CONTROLS .................. .. .. .. .... ........ .... .... ........ .... .......... .. .. .............................. .. .................... 5
3. OPERATION . ........ .... .... .. .. .. ... ........ . .. .............. .. .. ...... .......... .. ........ .. ...................................... 7
3.1. GENERAL CONSIDERATIONS ............. ........................................... . ........... 7
3.2. BATIERY CONSIDERATIONS .... ................................................. . .............. . 7
3.3. MOUNTING OF MICROPHONE ....... . ...................................................... .. .. . 7
3.4. CALIBRATION .... .. . ....... . ........................................................................... 8
General ............ . .......................................................................... . .. ......... 8
Calibration with Microphone Type 4148 ..................................................... 8
3.5. SOUND MEASUREMENTS ......................................................................... 8
General ................................................................................................... 8
Procedure
for Sound Measurements ........................................................... 9
3.6. LOCKING OF CONTROLS .......................................................................... 9
Locking
the Attenuator .......................................................................... .... 10
Locking the Weighting Networks ................................................................ 11
3. 7. CHARACTERISTICS ....... . .......................................................................... 12
Use
of A & C Weighting Networks ............................................................. . 12
Output Socket .......... ...... ............................. ; ............................................ 13
Frequency Response ............................ . ..................................................... 13
Influence of Reflections ..... . .............................................................. . ........ 13
Directional Characteristics ......................................................................... 13
Effect
of Vibrations .. .. . .............................................................................. 15
3.8. USE WITH PINK NOISE TEST RECORD OR 2011 ................................ ......... 15

FEATURES 2206:
• Fulfils IEC R 1 79 and
ANSI S 1.4 - 1971 Type 1
for precision sound level
meters
• Special B &K 1 /2"
Condenser Microphone
• A and C-weighting
networks
• Linear position
FEATURES 2208:
• Hold circuit for maximum
A-weighted noise level
• Store
for held value
•
Fulfils IEC R 1 23 and
ANSI S 1.4-1971 Type 2
for general purpose sound
level meters
• B & K 1" Piezoelectric
microphone
• A-weighting network
• Easy conversion for
"Precision" measurement
COMMON FEATURES:
• Fast and Slow meter
damping
• Dynamic range up to
140 dB SL ( 130 for 2208)
• 0 utput for Tape Recorder,
or Level Recorder
• Light weight approximately
0,8 kg (28 oz)
• Large tilted meter for easy
reading
USES:
• Sound
measurements in
industrial work areas to
check for health hazards
• Traffic noise measurement
16-085
types 2206 and 2. 208
Miniature Sound Level Meters
2206
• Building noise, insulation
and distribution surveys
• Community noise surveys
• Product noise
measurements for
development and quality
control
•
Measurements on
electroacoustic systems
These miniature sound level me-
ters provide a quick and reliable
method of determining noise level.
They are the ideal tools for noise
abatement engineers, traffic police,
2208
industrial hygienists, public health
inspectors and others whose con-
cern it is to keep noise at a toler-
able level in our modern industrial
society.
Portable sound level meters can
be used
profitably for an initial sur-
vey of noisy environments and
then , where necessary, a more de-
tailed analysis can be made using
more complex instrumentation . The
big advantage·
of these miniature
meters however, is that their simple
operation makes them suitable for
use ·by people without the technical
knowledge to handle the more com-
plex equipment.

Battery 1.5 Vo------<rr
On
OQff
'2206 ----------,
I Condenser
I Microphone Polarization Voltage
Adapter
(Source
follower)
~~ (Type~4-1_48_) ...__-1
L- -- - _...._____. J
~ Pl.,oeloct~ ~ - - - -~
Microphone
I (Type 4117) I
I I
l220!_ _______ j
Meter
Voltage Voltage
Converter Regulator
~~-----
Hold
1
I L-----'
I
lsi ow
I
I
2206
l._f
208
only _j Rectifier
Output
740632
Fig.1. Block diagram for the miniature sound level meters
Description
The Type 2206 Precision Sound
Level Meter and Type 2208 Noise
Event
Meter are two variations of
the same basic instrument. Both
meet the internationally apprbved
standards
for general purpose
sound level meters, while the Type
2206 also satisfies the require-
ments for precision sound level me-
ters.
Various special features have
been
included in the two instru-
ments so that a sound level meter
can be obtained with only those fea-
tures necessary for its particular
use. This gives an instrument that
is both inexpensive, and simple to
operate. Reference to the block dia-
gram in Fig.1 shows the similarities
and differences between the instru-
ments.
The microphone normally sup-
plied with the Type 2208 is the 1"
diameter Piezoelectric Microphone
Type 4117. This is a high quality,
low cost measuring microphone de-
signed primarily for use in general
purpose sound level meters. Its
high capacitance allows it to be
used
with amplifiers having moder-
ate input impedance to give ade-
quate
low frequency performance.
The high capacitance also permits
the use of relatively long connection
cables between the microphone and
the
sound level meter (reducing the
2
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Briiel & Kj(8r Potentiometer Ronge, __ dB Ro<tilier, __ L- lim. Froq. :_Hz 'VIr . Spoed: __ mmf- . Popo< Spoed:_....,..c.
C-hogon 50 25 , 10 75
dB dB Condenser Microphone 4148:=f dB dB
860
Moosuring Obj.:
Microphones Piezoelectric Microphone 4117
~~u~~n~:~;~ 30 15
Meters
()0 Free Field
---2010
---·105
~
o.u:._
Sign.: 0 0
430
10dB
2 15
Qp 1124 10
20 Hz 50 100
200
500 1000 2000 5000 0 0
10000 20000 40000 D A B C lin.
Multiply Fre<{vency Scole by
Z.ro t.....l:
1612/2112 A B C lin. 17 2221
Fig.2. Typical frequency response curves for the microphones
possibility of reflections from the op-
erators body) without serious loss of
sensitivity. A typical frequency re-
sponse
curve is shown in Fig.2. The
performance of the 2208 with this
microphone is in accordance with
IEC R1 23 for general purpose
sound level meters.
The Type 2206 features a special
8 &K condenser microphone sys-
tem, and the drcuitry for 2208 has
also been designed to accept this
system. The Type 4148 1 /2" Con-
denser Microphone requires 28 V
polarization voltage, and was devel-
oped for these miniature instru-
ments. It is mounted on the meter
by means of the UA 0208 Adaptor,
and when fitted, the requirements
of IEC, ANSI and DIN for precision
sound level meters are met. The
Adaptor contains a source follower
(FET) to transform the high imped-
ance of the condenser microphone
into a low output impedance. A typi-
cal frequency response curve for
the 1 /2" Condenser Microphone is
also shown in Fig.2. When fitted
with the 1 /2" Condenser Micro-
phone and Adaptor, the 2208 be-
comes a Precision
Sound Level Me-
ter in accordance with IEC, ANSI
and DIN.
The Piezoelectric Microphone, or
Condenser Microphone and Adap-
tor, can be replaced by a JJ 0037
Adaptor, which permits connection
with miniature coaxial cables, thus
allowing the sound level meters to
be used as indicating instruments
for 8 & K accelerometers. It should
be noted however, that when the

2208 is used for viQration measure-
ment , the weighting network will
influence the readings making accu-
rate calibration extremely difficult.
Nevertheless, the accuracy is suffi-
cient for quick estimates of vibra-
tion level.
Two attenuator stages are pro-
vided, and these are connected to-
gether so that the 10 dB steps in
range are obtained with the best
possible signal to noise ratio. To
simplify readout, the range selected
is displayed in a window on the me-
ter scale . On the 2206 a separate
push-button switch operates in the
first amplifier stage. This can be
used
to increase the measuring
range quickly by 10 dB, regardless
of range setting, to allow for sud-
den high levels. The range control
switch on both instruments can be
locked internally , in any of its ten
positions (30 to 120 dB), to prevent
inadvertent range changes when
the instrument is to be used by in -
experienced personnel . The use of
the "+ 10dB" button is retained
while the range selector is locked.
Type 2206 is equipped with the
A and C-weighting networks and
has, in addition, a linear position.
The 2208, being equipped with a
maximum hold circuit, has only the
widely used A-weighting network.
The network selector switch can
also be locked to prevent accidental
changes which could cause false
readings. The A and C-weighting
characteristics are shown in fig . 3.
The second amplifier stage feeds
the rectifier and an AC output termi-
nal. The output is used with Tape
Recorders
or Level Recorders. (See
Fig.4) .
The rectifier gives correct RMS
values within 5% for signals with
crest factors up to 3 at full scale me-
ter deflection . The internationally
standardized "Fast" and "Slow " me -
ter damping characteristics are pro-
vided. The meter is a DC moving
coil instrument with ribbon suspen-
sion . The angled meter scale is eas-
ily read, with graduations from
-1 0 dB to + 10 dB over a 5, 5 em
(2,25 in) scale length .
In
the Type 2208, a special cir-
cuit can hold the maximum meter
deflection that occurs during a
measurement. This feature is partic-
ularly useful for measurements of
rapidly changing levels such as traf -
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oo ooooooooo o ooooooooooooooooooooooooooooooooooooo
ruei&Kjcer Potenti ome te r Rang e: -- dB Re ctifier:- - Low er Lim Fr e q. :- Hz Wr Sp eed :- mm / s ec Pape rSpeed :- mm /sec.
Cop e nhag en 50 25 10 75
+
dB dB
dB dB
40 20
8 60
M e asur i ng Ob j .: f== f:= C
--- 3015
6 45
- -- 2010
4 30
10 dB
-- - 10
2 15
R ec . No .:
Dat e __ = f:= A
Sign .: __ 0 0
10 20 Hz 50 100
200 500 1 000 2000
Qp 11 24
M ul ti pl y Fre qu en cy Sca le by Zero Level:
Fig.3. Typical A and C-weighting characteristics
74 0634
Miniature Sound
Level Meter
2206 or 2208 Level Recorder 2306
Fig.4. Portable set-up for recording
levels
fie noise. When the METER RESET
button is depressed the meter de-
flection is cleared, and the instru-
ment is ready for the next measure -
ment. In addition , a held level can
be
stored, to prevent loss of the
reading if subsequently a higher lev-
el
occurs . This is achieved by turn-
ing the Function Selector to
"Store", which grounds the incom-
ing signal to prevent it from reach-
ing the meter . The hold circuit can
be by-passed
allowing the Type
2208 to be used as a general pur-
pose sound level meter.
Another version, the Precision
Sound Level Meter Type 5606 is
available on special order for vehi-
cle noise measurements to ISO
R 362 (moving vehicles) and the pro-
posed ISO method for noise meas-
urements on stationary vehicles.
+ 1
dB 0
- 1
c - 2
0
· ;;
Deflection in
Similar to a Type 2208 with a Con-
denser Microphone, the Type 5606
features a speical max . hold circuit
that can be externally controlled.
This enables a tachometer to trigger
the hold function when a preset en-
gine speed is reached .
The curves in Fig.5 show the rela-
tive meter deflections to be ex-
pected
on the 2208 in position
"Fast" with MAX. RMS HOLD
switched to "On" and "Off" for dif -
ferent impulse durations. The dot-
ted line indicates that in position
"fast", HOLD "Off'' , the meter de-
flection will return to the real value
for a steady state signal with dura-
tion longer than about 1 second.
The overshoot in position "Fast",
Hold "Off" is as specified by IEC
R 179.
Calibration may be performed
with either the Type 4230 Sound
Level Calibrator (94 dB at 1000Hz).
or with the Type 4220 Pistonphone
(1 24 dB at 250Hz) . Because the
2208 sound level meter registers
the . weighted sound level, a correc-
tion factor must be applied when
using the Pistonphone with this in -
strument .
------
- ........ ._
~-----
~
~
./
~
- 3
't
-4
pos . " Fast", Hold "on" ,
~
0
Q)
- 5
~
- 6
~
- 7
· ~
-8
Q;
a: - 9
-10
- 11
- 12
- 13
-14
~v
//
/A
//
"
//
Ma x. deflection in pos . "Fa st ", Hold "off"
//
//
//
/V
//
ff'
20
50 100 200 500
msec . 1
sec .
171007
Impulse Duration
Fig.5 . The relationship between Impulse Duration and Relative Meter Deflection for the 2208
3

Specifications
B & K Type Number
2206
220B
Measuring Range:
39 to 135 dB(A)
32 to 1 30 dB(A)
51
to 135 dB(C)
58 to 135 dB(Lin)
Signal to Noise Ratio:
Better than 5 dB for the lower limit .
Weighting Networks:
A and C plus Linear
A
(20Hz to 16kHz(± 3 dB))
Meter Scale:
Graduations from -10 dB to+ 10 dB. Range displayed in window
Meter Damping:
Fast and Slow to IEC standard 179, ANSI S1. 4-1971 and DIN 45 633
Rectifier Accuracy:
± 5% for signals with crest factors less than 3
Hold Circuit Accuracy:
Held
meter deflection
corresponding
to
maximum
RMS "Fast" response ± 2 dB
Better accuracy with durations longer than 1 s (see
Fig.5)
Hold Decay:
Less than 1 dB in 5 minutes at 25°C (77°F)
Store:
Any held value can be stored
Reset: Push button resets meter
Input Impedance: > 2000 MO / I 40 pF
10 MO / / 140 pF
output Impedance: Less than 50 0
Minimum Load Impedance :
50000
Output Voltage:
Approximately 2,5 V RMS for full scale meter deflection
Maximum Output :
20V peak to peak
Distortion:
Less than 1% for full scale meter deflection
Noise: (A-weighted) Less than 3,1 t-N relative to input with 17 pF across Less than
1,2/.N
relative to
input with 4000 pF
input
across input
Microphone Type: B & K 1/ 2" Condenser Type 4148
B & K 1" Piezoelectric Type 4117
(28 V DC polarization Voltage)
Microphone Frequency Linear ± 2 dB between 4Hz and 16kHz for incidence
Linear ± 3 dB between 4Hz and 10kHz for incidence
Response: perpendicular to the diaphragm in a free field perpendicular to the diaphragm in a free field
Individual calibration curve supplied Individual calibration curve supplied
Microphone Sensitivity: Approx . 14 mV per N/ m2
Approx . 3 mV per N/ m2
Microphone Capacitance:
17 pF 4000 pF
Microphone Temperature
- 0,015 dB/ °C (-0,0083 dB /° F)
Coefficient :
Battery Type: Single " C" cell, IEC R 14 . (B & K order number QB 0009)
Battery Life: 10 hours continuous operation
5 hours continuous operation
Operating Temperature :
-10 to+ 50°C (+ 14 to+ 122°F)
Storage Temperature (battery
-20 to + 70°C (-4 to + 1 58°F)
removed):
Humidity Range:
Up to 90% relative humidity
Dimensions: Length:
235 mm (9,2 in)
186 mm (7,3 in)
Width: 84 mm (3,3 in)
84 mm (3,3 in)
Height:
51 mm (2,0 in) 51
mm (2,0 in)
Weight: 0,83 kg (29 oz) including battery
0,8 kg (28 oz) including battery
Accessories Included : Condenser Microphone 4148
Piezoelectric Microphone 4117
Microphone Adaptor UA 0208
Windscreen UA 0207
Windscreen UA 0237
Carrying Case KE 0060, Pistolgrip Handle DH 0129, Wrist Strap DH 0128 , Screw Driver QA 0001
1,5 V Battery IEC type R 14 ("C" size) QB 0009
Accessories Available:
Set of 6 spare Windscreens UA 0254
Set of 6 spare Windscreens UA 0253
3 m Extension Cable AO 0063 6 m Extension Cable AO 0061
Input Adaptor for accelerometer cable JJ 261 5
Condenser Microphone 4148
Microphone Adaptor UA 0208
Set of 6 Windscreens for 1/ 2" Microphone UA 0254
Sound Level Calibrator 4230, Pistonphone 4220 , 1,2 m Output Cable AQ 0037, Tripod UA 0049
Input Adaptor for accelerometer cable JJ 0037
4