BRUEL & KJAER 2221 User manual
Instruction
Manual
Precision Integrating Sound Level Meters
Types
2221
and
2222
1-0330601-1A
BE
0601
__,.,
__
,_
.,_
,.
--
..
oiiW
..
II
Pocket-sized
Preco:lslon
Integrating Sound
Level
Meters
complying with Proposed IEC
standard
for
Precision Integrating Sound
Level Meters Type 1
P,
and relevant sections
of
IEC
651
type 1, DIN-IEC
651
Klasse 1,
ANSI S1.4.1971 type 1, and BS 5969 Type
1.
It measures
Leq
over periods up
to
2,
77
hours, SEL and Max. Hold "Fast/Slow" and
"Peak". The measuring range
from
25
to
145 dB Is covered In
four
overlapping sub-
ranges and the results are
directly
shown on
a
digital
display with
0,1
dB resolution. An
AC
output
Is provided
for
recording
pur-
poses. It Is supplied with Prepolarlzed
Con-
c;:tenser
Microphone Type 4176.
Types
2221
and 2222 are Identical
except
that
the Type
2221
has a "Fast" time weight-
ing, whilst the Type 2222 has a "Slow" time
weighting.
+ Briiel &Kjaer
Precision Integrating Sound Level Meters Types
2221
and 2222
Type
2221
from
serial
no. 1013675
Type
2222
from
serial
no. 851150
May
1982
CONTENTS
1.
INTRODUCTION
AND
SPECIFICATIONS
(PRODUCT
DATA)
...................................................................... 1
2.
CONTROLS
................................................................................................................................................................ 5
3.
OPERATION
...............................................................................................................................................................9
3.1. INTRODUCTION......................................................................................................................9
3.2. BATTERY INSTALLATION.....................................................................................................9
3.3. MOUNTING THE MICROPHONE........................................................................................ 10
3.4. CALIBRATION....................................................................................................................... 10
3.5. SOUND LEVEL MEASUREMENT .......................................................................................
11
General..................................................................................................................................
11
Considerations
Regarding the Type
of
Sound Field...................................................... 12
Leq
and SEL Measurements............................................................................................... 14
Max
Hold
"Fast/Slow"
Measurements............................................................................. 14
Max. Hold
"Peak"
Measurements..................................................................................... 15
Use
of
the L6qlSEL Conversion Table.............................................................................. 15
Noise Dose Evaluation.....................................................................................................
...
17
Example
of
Measurement.................................................................................................. 17
4.
USE
WITH
OTHER
INSTRUMENTS
................................................................................................................... 19
4.1. USE WITH LEVEL RECORDER TYPE 2306 .................................................................... 19
4.1. USE WITH TAPE RECORDER TYPE 7005/06.................................................................
21
Recording with
Direct
and FM Units................................................................................
21
Recording with the
Compander
Unit...................................:............................................
22
5.
APPENDIX
................................................................................................................................................................23
6.
SERVICE
AND
REPAIR......................................................................................................................................... 24
USES:
•
Determination
of
Leq
for
assessment
of
hearing
loss
risk
or
noise
annoyance.
•
Measurement
of
cyclical
machine
noise
•
Determination
of
Sound
Exposure
Level (SEL)
•
Measurement
of
Max.
noise
levels
•
Spatial
averaging
of
machine
noise
•
Sound
power
level
measurements
according
to
survey
method
FEATURES:
•
Direct
indication
of
Leq
and
SEL
•
Fulfils
proposed
IEC
standard
for
Precision
In-
tegrating
Sound
Level
Me-
ters
Type
1
P,
and
relevant
sections
IEC
651
Type
1,
DIN-IEC
651
Klasse
1 and
ANSI S1.4.1971
Type
1
•
Max.
Hold
"Peak"
•
Max.
hold
"Fast"
(2221)
or
Max.
hold
"Slow"
(2222)
•
Easily
read
digital
display
•
Light
and
compact
•
AC
output
for
recording
•
Delivered
with
individually
calibrated
Condenser
Microphone
• 60
dB
dynamic
range
•
Comprehensive
display:
overload,
underrange,
bat-
tery
state,
frequency
weighting,
overflow
1-044
0059-2A
BP 0059
types
2221 and 2222
Precision
Integrating
Sound
Level
Meters
In
addition
to
offering
Type 1 mea-
surement
characteristics,
these
Preci-
sion
Integrating
Sound Level
Meters
are
truly
portable.
Just
over
20 em
long, 2,4 em
thick
and weighing 400 g,
they will easily
fit
in
your
pocket.
The use
of
microprocessor
technol-
ogy
results in accurate,
true
measure-
ments and
simplicity
of
use.
Leq•
SEL,
and
"Peak"
and
"Fast/Slow
" Max.
Hold
are
indicated
on a
large
digital
display
making
reading
errors
virtual-
ly impossible. In
addition
to
these
ba-
sic functions, the Types
2221
and 2222
have a pause function which
greatly
extends the
applications
of
the
instruments
.
The
comprehensive
digital
display
and
the
functional
simplicity
permit
confi-
dent
and
efficient
use
of
this Sound
Level Meter.
An AC
output
allows
recording
of
the
weighted
input
signal.
Introduction
Today,
noise
is an
important
con-
sideration
in
many
areas
of
the
envi-
ronment
and
noise
measurements
are
no
longer
carried
out
exclusively
by
specialists.
With
this
in
mind,
B & K has
developed
the
Precision
Integrating
Sound
Level
Meters
Types
2221 and 2222.
These
instru-
ments
have
all
of
the
features
neces-
sary
for
a
wide
variety
of
noise
mea-
surements
and
comply
with
the
pro-
posed
IEC
recommendation
for
Inte-
grating
Sound
Level
Meters
Type
1P
and IEC
651
Type
1,
DIN-IEC
651
Klasse
1
and
ANSI S1.4.1971
Type
1
standards.
The
Types
2221 and 2222
carry
out
basically
4
measurements:
Leq•
SEL,
Max.
Hold
"Fast"
(Type
2221)
or
"Slow
"
(Type
2222),
and
Max.
Hold
"Peak";
all in
four
sensitivity
ranges.
.......
_
__,
..
A -
18
- -
108
z•
- •
4IIW
•
II
Pnociloian
·~..,_.......,
,._
M-
-
...... -
Off
On
8M116
Kjllf
+ Type
2222
Leq
Measurements
Leq is
the
A-weighted
noise
level
averaged
over
the
measurement
pe-
riod
. It
can
be
considered
as
the
continuous
steady
noise
level
which
would
have
the
same
total
A-weight-
ed
acoustic
energy
as
the real
fluctu-
ating
noise
over
the
same
period
of
time
. The
measurement
of
Leq
is
based
on
the
equal
energy
principle:
1
JT
p(t)
2
Leq =
10
Log10
- (-
-)
dt
T o Po
where
Po
is
the
reference
sound
pressure
(20
~LPa),
p(t) is the
A-
weighted
time
varying
sound
pres-
sure
and
T is
the
time
interval
over
which
it
is
measured.
SEL
Measurements
Sound
Exposure
Level (SEL) is the
constant
level
which
if
maintained
for
a
period
of
1
second
would
have
the
same
A-weighted
acoustic
ener-
gy
as
the
measured
noise
event, and
is
defined
as:
1
/+oo
(p(t))2
SEL =
10
Log10 - -
dt
Tref
_oo
Po
Tref = 1s
The SEL is
used
primarily
to
de-
scribe
and
compare
single
events
(e.g.
vehicle
pass-by,
etc.).
Max.
Hold
"Fast/Slow"
This is
the
maximum
A-weighted
RMS
sound
level
measured
with
the
standardized
"Fast"
(Type
2221)
or
"Slow"
(Type
2222)
time
constant,
over
the
measurement
period.
It
is
used
for
fluctuating
noises.
Max.
Hold
"Peak"
The
peak
value
of
impulsive
noises
is an
important
factor
when
consid-
ering
hazard
to
hearing.
The
rise
time
is 30
J.LS,
and
the
frequency
re-
sponse
linear.
Description
Principle: (see
block
diagram)
The
basic
function
of
the
instru-
ment
is
to
perform
the
Leq
measure-
ment/calculation
for
any
period
up
to
2,
77
hours.
The
Leq
measurement
principle
is
described
in
greater
de-
tail
below
since
the
SEL and
Max.
Hold
functions
are
obtained
on
the
basis
of
Leq
measurement.
The
amplified
and
A-weighted
sig-
nal
from
the
microphone
is
squared
through
the
log
and
antilog
convert-
ers. The
integrator
summates
the
signal,
generates
an
impulse
and is
reset
when
a
trigger
level is
exceed-
ed. The
impulse
repetition
rate
is
proportional
to
the
square
of
the
in-
stantaneous
value
of
the
input
sig-
nal, and
the
number
of
impulses
is
thus
proportional
to
the
noise
dose
received
since
the
beginning
of
the
measurement.
The
impulses
are
ac-
Cl;Jmulated
by
a
dose
counter.
A
crystal
oscillator
generates
clock
pulses
which
are
accumulated
in
the
time
counter.
From
the
two
counter
outputs
the
Leq
calculation
is
carried
out
by
the
microprocessor
and
re-
peated
every
0,5 s
updating
the
dis-
play.
Dose
and
time
counters
are
only
set
to
zero
when
the
instrument
is
reset.
2
Amplifier
.a.
.a.-
"A"
weighting
for
Leq•
SEL,
Max.
Hold
Fast/
Slow
-Linear
(flat)
weighting
for
Max.
Hold
Peak
• - " Fast"
for
Type
2221
- "
Slow"
for
Type
2222
Integrator
(DC/f converter)
Clock
genera
tor
AC
Output
T
Max. hold
Ma
x.
Hold
Antilog
converter
1
/T
p2 (t)
dt
Leq =
10
Log T -
p-
2-
0 0
Micro
·
processor Digital
display
*
Automatically
reset once per second
in Max.
Hold
T = 1
sec
. in
SE
Land
Max.
Hold
8113 13
Fig.1.
Simplified
block
diagram
of
the
Types
2221
and
2222
The SEL
measurement
procedure
is
identical
to
the
Leq
procedure,
ex-
cept
that
a
time
of
1 s is
used
for
the
calculation
instead
of
the
time
given
by
the
time
counter.
It is
possible
to
switch
between
Leq
and SEL
without
interrupting
the
measurement.
For
Max.
Hold
functions
the
loga-
rithm
of
the
instantaneous
signal
is
first
applied
to
the
Max.
Hold
circuit,
the
output
from
which
is
then
applied
to
the
Leq
circuits
for
normal
pro-
cessing.
The
Leq
of
a
constant
signal
is
equal
to
the
instantaneous
value
of
the
signal
itself.
Therefore
the
val-
ue
obtained
after
an
Leq
calculation
has
been
made
on
the
Max.
Hold
output,
is
equal
to
the
maximum
val-
ue.
For
Max.
Hold
"Fast/Slow"
the
output
is
equal
to
the
maximum
A-
weighted
signal
measured
with
the
standardized
"Fast/Slow"
time
con-
stant; and
for
Max.
Hold
"Peak"
the
output
is
equal
to
the
maximum
in-
stantaneous
value
of
the
signal
after
"Linear"
(20 Hz -20 kHz)
filtering.
Microphone
Types
2221
and 2222
are
equipped
with
a
Prepolarized
Condenser
Mi-
crophone
Type
4176.
This
micro-
phone
is
designed
to
have
a
linear
oo
incidence
free
field
response
for
measurements
in
accordance
with
IEC
standards,
and is well
suited
for
free
field
conditions,
e.g.
most
out-
door
situations.
When
fitted
with
the
Random
Incidence
Adaptor
supplied
a
linear
random
incidence
response
according
to
ANSI
standards
is
ob-
tained,
which
generally
gives
more
accurate
results
for
indoor
measure-
ments.
The
frequency
responses
and
directional
characteristics
of
the
complete
instrument
are
given
in
Figs
3
to
5.
An
individual
calibration
chart
for
the
microphone
is
supplied
with
the
instrument.
Input
Stage
The
removable
input
stage
has
a
very
high
input
impedance
to
match
the
high
impedance
of
the
micro-
phone.
The
output
impedance
is
low
to
allow
extension
cables
to
be
in-
serted
between
input
stage
and
sound
level
meter.
Weighting
Network,
Attenuator
and
Overload
Indicator
The
selection
of
A
or
Linear
(flat)
weighting
is
automatically
made
by
the
"Function"
switch.
The
A-weight-
ing
is
applied
to
the
signal
for
Leq•
SEL and
Max.
Hold
"Fast/Slow"
measurements;
linear
weighting
is
only
obtained
for
Max.
Hold
"Peak"
measurements.
These
weightings
are
also
applied
to
the
AC
output.
A-weighted
"Peak"
measurements
may
be
obtained
by
modifying
the
instrument.
The
actual
weighting
ap-
plied
is
indicated
on
the
display.
The
input
amplifier
covers
the
range
25
to
145
dB
in
four
overlap-
ping
sub-ranges.
An
overload
indi-
cator
monitors
input
and
output
sig-
nal
levels
of
the
amplifier
and
if
an
overload
occurs
,
the
display
shows
"•
". It
disappears
only
when
the
in-
strument
is
reset.
For
Max.
Hold
functions
the
lower
limit
of
the
mea-
suring
range
is
15
dB
higher
than
for
the
Leq range.
Leq
Calculation
The
Leq
is
calculated
over
a
maxi-
mum
period
of
2,77
hours
which
is
the
limit
of
the
time
counter.
After
this
time,
the
display
shows
"*"
to
indicate
that
the
Leq
value
now
dis-
played
is
incorrect.
However,
the
SEL
value
is
not
affected
by
this
time
limitation
as
it
is
always
calculated
using
a
time
period
of
1
second.
A
conversion
table
on
the
reverse
side
of
the
instrument
gives
the
Leq
over
any
period
from
the
SEL
value
and
the
elapsed
time.
Digital
Display
Measurement
values
are
shown
on
a
3112
digit
display
,
with
a
resolution
of
0,1 dB. It is
updated
every
112
sec-
ond
for
Leq and
SEL
measurements,
and
every
1
second
for
Max.
Hold
measurement.
The
following
charac-
ters
may
also
be
displayed:
"A":
A-weighted
frequency
response
"L":
Linear
(flat)
frequency
response
"*
":
Maximum
Leq
measuring
time
exceeded
"•":
An
overload
has
occured
dur-
ing
the
measuring
period
"~":
The
sound
pressure
level is
un-
der
the
minimum
range
level
"BAT":
Batteries
must
be
changed.
"00.0":
Initial
display
check
dB
+4
+2 '
.........
" - - -
":
Underrange
in
Max.
Hold
measurements
and
delay
after
Reset
Power
Supply
Power
is
supplied
from
3
alkaline
batteries
(IEC R 20)
which
will
pro-
vide
approximately
10
hours
of
con-
tinuous
operation
.
_.
I,
..
,,
..
I
I*
B~T'
Lf
0.
-,A
Fig.2.
Display
of
Types
2221
and
2222
~
o
l
~
r
a~ce:
I~C
k51
.,..-
--
I I
ty
pe 1
I I
--
Max.
Hold
Fast/Slow
and
Max.
o
...-
.......
F
ree
-f
ie
ld
response_
--
"'
"""\.
Hold
Peak
calculation
When
Max.
Hold
is
selected
the
output
signal
from
the
log
converter
is
fed
directly
to
the
Max.
Hold
cir-
cuit
if
"
Peak
" is
required,
or
via
an
averaging
circuit
for
Max
.
Hold
"
Fast/Slow"
measurements.
The
output
from
the
Max.
Hold
circuit
is
fed
via
the
antilog
,
integrator
and
counte
r
circuits
to
the
microproces-
sor
which
controls
the
1 s
updating
and
display
of
the
Max.
Hold
readings.
Both
instruments
can
be
modified
to
obtain
Max.
"Slow
"
instead
of
Max.
"Fast
"
and
vice
versa.
Pause
The
Types
2221
and
2222
have
a
"
Pause
"
function
which
in
the
"L
eq"
and "SEL"
modes
,
interrupts
the
measurement
without
resetting.
This
can
be
used
for
example
when
the
instrument
is
moved
from
point
to
point
for
spatial
averaging
of
the
no
ise
from
a
sound
source
.
In
Max
.
Hold
modes
the
"
Pause
"
function
freezes
the
display
,
but
any
higher
signal
occuring
while
in
"
Pause
"
will
be
displayed
when
com-
ing
back
to
"Run
".
Reset
The
instrument
is
reset
either
automatically
when
changing
be-
tween
measuring
ranges
and
func-
tions
(except
between
L
eq
and
SEL)
or
manually
by
push
button
.
The
new
measurement
begins
112
second
later
to
avoid
measuring
the
switch
noise.
"-,
"\
/ '-,
- 2
- 4
'\
10 20 100 200 1 k
2k
10 k 20 k
Frequency (H
z)
8
11
3 11
Fig.3.
Typical
free
field
frequency
response
of
the
complete
instrument
with
0°
incidence
shown
as
deviation
from
the
standardized
A-curve
dB
+4
~
+2
0
I---
- 2
./
- 410
.........
"'-
""'""""r-....
-.....,
./.,_v
....,......v
20 100 200 1 k 2 k
Frequency
(Hz)
Tolerance: ANSI S 1.4
.-
1971
· -
V1 l
Typ
e
1A
...,...f.-
1--
I I I I
With Random
...
~
Incidence
Ad
a
pt
or
I\
Withou
t Ra
ndom
r\~
\l~c
i
den
c e
Adaptor
"
V\1
I I I
\I I I I
10 k 20 k
8113
12
Fig.4.
Typical
diffuse
field
frequency
response
of
the
complete
instrument
shown
as
deviation
from
the
standardized
A-curve.
Fig.5.
Directional
characteristics
of
the
complete
instrument
3
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.
FUNCTION:
2.
CONTROLS
Random Incidence •
Adaptor
Microphone
------
1
Microphone
Adaptor
------
1
leq
f'anta
·-
··
·-
··
Range Selector
--+---•
::':
...,
Display
--+---
Mode
,_
Windscreen
--+--Reset
Mode
Selector
--+---
1tua
,.....
Off
Oa---t--
On -Off
llriW
a~Q~W
+ Type
2222
Fig.
2.
1.
Front
view
of
the
Sound
Level
Meter
Four
position
slide-switch
for
selection
of
the
operating
mode
as
follows:
"Leq": The
current
Leq
value is
displayed
and
updated
twice
per
sec-
ond. The
maximum
measurement
period
with
direct
display
of
the result
is
2,
77 hours.
For
measurements
over
periods
longer
than
2,
77 hours,
the
Leq
can be
determined
from
the
SEL
value and the elapsed
time
(see
section
3.5.7).
"SEL":
Operates
the
SEL
calculation
mode, and the measurement
result
is
directly
displayed.
The
measurement
period
is only
limited
by
the
battery
life.
5
Leq
RANGE:
MODE:
6
Leq
dB(A)
25-85
45-105
65-125
85-145
"Max.
Hold Fast" (2221 only):
Holds
the
maximum
RMS
signal
value
measured
with
the
standardized
"Fast"
time
weighting
until
the
meter
is
reset. (See
Chapter
5).
"Max.
Hold Slow" (2222 only):
Holds
the
maximum
RMS
signal
value
measured
with
the
standardized
"Slow"
time
weighting
until
the
meter
is
reset. (See
Chapter
5).
"Max.
Hold Peak":
Holds
the
maximum
"Peak"
value
until
the
meter
is
reset. Rise
time
is
<30
f..LS.
Switching
the FUNCTION
selector
automatically
resets
the
instrument
except
between
Leq
and SEL
positions.
Leq•
SEL and
Max.
Hold
"Fast/S-
low"
measurements
are
A-weighted,
while
Max.
Hold
"Peak"
is
made
with
a
Linear
(flat)
weighting.
The
weighting
selection
is
made
automati-
cally
by
the FUNCTION
selector,
and
"A"
or
"L"
appears
on the
display
as a
reminder.
Four
position
slide-switch
providing
four
overlapping
measuring
ranges. See
Table
2.1.
Max. Hold
"Fast/Slow"
Max. Hold
"Peak"
dB(A)
dB{
lin.)
40-85
55-88
60-105
60-108
80-125
80-128
100-
145
100-148
8111
32
Table
2.
1.
Measuring
ranges
for
the
differents
functions
The
measurement
ranges
obtained
are
different
depending
on
which
function
is selected. SEL and
Leq
measurements
use
the
same
ranges;
note
however,
that
for
SEL
measurements
the
range
values
applies
to
the
instantaneous
RMS level and
not
to
the
SEL value
displayed.
When
switching
between
measuring
ranges,
the
instrument
is
automatically
reset.
Two
position
slide-switch
with
the
following
functions:
"Run":
Normal
operating
mode.
The
measurement
selected
by
the
FUNCTION
switch
is then in
progress.
"Pause":
Interrupts
the
measurement
when in
Leq
or
SEL
function.
Measurement
will be
continued
when
returning
to
"Run".
For
Max.
Hold
functions
it
freezes
the
display.
A
higher
level
occuring
while
in
"Pause"
position
is
held
by
the
max.
hold
circuit
and
displayed
when
returning
to
"Run".
POWER:
RESET:
Two
positions
slide-switch
connecting
power
to
the
instrument.
Resets
the
time
and
dose
counters
plus
max.
hold
detector.
The
mea-
surement
starts
after
0,5 s
delay
in
order
to
avoid
switching
noise.
SENSITIVITY ADJUSTMENT:
Multiturn
potentiometer
to
calibrate
the
instrument
sensitivity.
Sensitiv-
ity
is
increased
when
turning
clockwise.
Access
to
the
potentiometer
is
protected
by
a
removable
plastic
lug.
AC
OUTPUT:
DISPLAY:
2,5
mm
mini-jack
socket
accepting
Plug JP 0213
and
Cable
AO 0173
for
level
recording.
The
maximum
signal
delivered
is 2 V RMS and
corre-
sponds
to
full range.
Output
impedance
1
kn,
short
circuit
protected.
Fig
. 2.2.
AC
Output
of
the
Sound
Level
Meter
3112
digit
liquid
crystal
display
for
readout
of
measurement
results and
the
following
indications:
"0 0.0":
Displayed
for
one
second
after
switching
on. This
display
is
followed
by
" " in
order
to
check
visually
all
segments
of
the
display.
.
-,
.-,
.-,A
Lf Lf.Lf
---A
b)
1;;;:=:::=:====:3
Fig. 2.3. a)
Display
check
b)
Underrange
in
Max.
Hold
(and
Reset)
BAT I
.-,
·=
·-·A
f ,_, L.l. '
a)
~
----------------
··
-,
'
.-,*
f
f.=f
A
b)
E=:===::z:=•
Fig. 2.5. a)
Battery
depleted
b)
Maximum
Leq
duration
exceeded
-,
I
t:IA
f ••
_,
~
,.-,.-
t'
f Lf 0 .
-,A
b)
IIIIIEIII!Ii!IIBIEE!!II
Fig
. 2.4. a)
Underrange
b)
Overload
•_=,
t_l
,-,A
I.L.f
.-,
.-,
.-
=-
ct=•
L
Fig. 2.6. a)
A-weighting
applied
b)
Linear
(Flat)
weighting
applied
7
TRIPOD MOUNTING BUSH:
RANDOM INCIDENCE
ADAPTOR:
WINDSCREEN:
8
"---"
(or
"
P--
"):
Displayed
during
the
0,5 s
time
delay
after
reset
(manual
or
automatic),
and
during
underrange
in
Max.
Hold.
measurements.
"T":
Indicates
that
the
current
sound
level
is
underrange.
Switch
Leq
RANGE
to
a
lower
range. The
sign
disappears
when
the
sound
level
exceeds
the
minimum
range
value.
"•":
Indicates
that
an
overload
has
occured
since
the
last
reset
and
the
displayed
value
may
be
incorrect.
This
warning
only
disappears
with
the
next
reset.
"*
":
Indicates
that
the
time
counter
capacity
has been
exceeded
dur-
ing
Leq
measurement.
The
Leq
value
displayed
is
incorrect,
but
the
SEL
value
remains
correct.
See
section
3.5.7
for
conversion
from
SEL
to
Leq·
The
sign
will
disappear
with
the
next
reset.
"BAT":
Indicates
that
the
power
supply
voltage
is
insufficient
and
that
batteries
have
to
be
changed.
See
section
3.2
for
battery
replacement.
"A":
Indicates
that
A-Weighting
is
applied.
It is
automatically
selected
by
the FUNCTION
switch
when
set
for
"Laq",
"SEL"
or
Max.
Hold
"Fast/Slow"
measurements.
See
Chapter
5.
"L":
Indicates
that
Linear
(flat)
weighting
is
applied.
It is
automatically
selected
by
the
FUNCTION
switch
when
set
for
Max.
Hold
"Peak"
measurement
only.
A
1f4"
UNC
threaded
bush
located
on
the
rear
of
the
instrument
for
tripod
mounting
Modifies
the
linear
0°
incidence
free
field
frequency
response
of
the
microphone
to
a
linear
random
incidence
response.
See
section
3.5.2.
Reduces
the
wind
noise
and
protects
the
microphone
against
dust,
condensation
and
light
precipitation.
It
is
recommended
for
all
outdoor
measurements.
Fig.
2.
7.
Reverse
side
of
the
Sound
Level
Meter
3. OPERATION
3.1.
INTRODUCTION
This
Instruction
Manual
describes
the
use
of
the
Precision
Integrating
Sound
Level
Meters
Types
2221 and 2222.
However,
more
general
considerations
on
sound
measurement
techniques
must
be
taken
in
account,
and
are
given
in
the
accompanying
booklet
"Mea-
suring
Sound".
To
obtain
valid
results
it
is
also
important
that
the
measurements
are
carried
out
according
to
the
relevant
national
or
international
standards.
3.2.
BATTERY
INSTALLATION
The
Type
2221/22
is
powered
by
3
alkaline
cells
1,5 V, IEC
Type
LR 6
(8
& K no. QB 0013).
These
must
be
replaced
when
"BAT"
symbol
is
indicated
by
the
display.
To
install
new
cells
slide
off
the
battery
compartment
cover.
See Fig.3.1.
Remove
the
depleted
cells
and
insert
new
ones
with
polari-ties as
shown
inside
the
battery
compart-
ment.
Slide
on
the
battery
cover
.
............
Fig.
3.
1.
Battery
replacement
It
is
recommended
to
use
only
alkaline
cells.
Other
types
of
dry
cell will have a
short
life
time
and
may
leak
when
exhausted.
New
alkaline
cells
will
provide
approximately
10
hours
of
continuous
operation.
Remove
the
batteries
and
keep
the
instrument
in a
dry
place
for
long
periods
of
storage.
9
3.3.
MOUNTING
THE
MICROPHONE
The
microphone
is
screwed
directly
onto
the
preamplifier,
using
light
finger
torque.
Note
that
the
protection
grid
is
not
removable
on
this
type
of
microphone.
A
fine
wire
gauze
fil-
ter
behind
the
protection
grid
prevents
dust
and
particle
penetration
to
the
diaphragm.
The
assembly
may
be
plugged
directly
into
the
Instrument
via
its
5
pin
DIN
plug
(see
Fig.3.2)
or
connected
via
a 3 m
or
10 m
extension
cable
available
under
order
numbers
AO
0185
and
AO
0186
respectively.
The
microphone
end
of
the
extension
cable
has
a
threaded
attachment
to
enable
it
to
be
connected
directly
to
a
standard
tripod
screw.
This
arrangement
allows
the
operator
to
remain
close
to
the
Sound
Level
Meter
for
reading
purposes,
while
at
the
same
time
enabling
him
to
be
well
away
from
the
microphone,
and
therefore
not
influence
the
.
sound
field.
Fig. 3.2.
Mounting
the
microphone
3.4. CALIBRATION
10
The
Sound
Level
Calibrator
Type
4230
is
used
for
acoustical
calibration
of
the
whole
Sound
Level
Meter,
including
the
microphone.
Due
to
the
quality
of
the
instrument,
calibration
should
only
be
necessary
from
time
to
time
and
should
require
very
little
adjustment.
If
a
large
adjustment
is
needed,
the
instrument
is
most
probably
defective
and has
to
be
checked
for
faults
(Consult
your
B & K
representative).
The
Type
4230
gives
a
nominal
sound
pressure
level
of
94
dB
± 0,3
dB
(re. 20 x
10-6
Pa).
The
calibration
procedure
is
as
follows:
1.
Remove
the
Random
Incidence
Adaptor
or
the
Windscreen
if
fitted.
2.
Set
the
controls
on
the
Sound
Level
Meter
as
follows:
FUNCTION:
"Leq"
RANGE: "45 - 105"
MODE:
"Run"
POWER:
"On"
3.
Fit
the
Sound
Level
Calibrator
with
a
112
"
adaptor
(B & K
no.
DB
0311)
over
the
microphone
4.
Start
the
Sound
Level
Calibrator
and
press
RESET
on
the
Sound
Level
Meter
5.
Wait
for
the
displayed
value
to
stabilize
and
read
the
display
which
should
be
93,8
dB
±0,1
dB.
6.
If
an
adjustment
is
necessary,
remove
the
plastic
plug
on
the
top
of
the
instrument
and
with
a
small
screw
driver
turn
the
potentiometer
a
few
degrees:
-
clockwise
if
the
displayed
value
is
less
than
93,8
dB
-
anticlockwise
if
the
displayed
value
is
greater
than
93,8
dB.
7.
Repeat
steps
4
to
6
until
the
correct
value
is
obtained.
Remove
the
Sound
Level
Calibrator
and
replace
the
plastic
plug.
Fig. 3.3.
Calibration
with
Sound
Level
Calibrator
Type 4230
3.5.
SOUND
LEVEL
MEASUREMENT
3.5.1.
General
Before
proceeding
with
a
measurement,
the
accompanying
booklet
"Measuring
Sound"
which
contains
useful
information
should
be
read
by
users
who
are
not
familiar
with
sound
measurements.
\
It
is
good
practice
before
starting
measurements
to
check
the
proper
functioning
of
the
sound
level
meter
and
its
calibration.
Always
use
the
windscreen
supplied
when
measure-
ments
are
made
outdoors
or
in
very
dusty
environments.
Keep the
instrument
at
arms
length
(or
mounted
on a
tripod)
to
minimize
body
reflections
which
can
produce
reading
errors
of
up
to
a
few
dB
in the
range
300
to
500 Hz.
3.5.2
Considerations
Regarding
the
Type
of
Sound
Field
12
The
condenser
microphone
fitted
to
the Type
2221/22
is
designed
to
have
a
linear
free
field
response
for
oo
incidence. Use
of
the
supplied
Random
Incidence
Adaptor
DZ 9566
results
in a
linear
response
under
diffuse
field
conditions.
The use
of
the
Random
Incidence
Adaptor
is
described
in the Fig.3.4 and.in the
following
text.
When
performing
measurements
to
national and
international
recommendations,
the
sound
level
meter
should
be
used as
prescribed
in the
relevant
standard.
Mount
Random
Incidence
Adaptor
Diffuse
Accurate
reading
ANSI
Free
Best
angle
of
incidence
75°
Inaccurate
reading
Remove
Random
Incidence
Adaptor
Diffuse
Inaccurate
reading
No
Remove
Random
Incidence
Adaptor
Free
Best angle
of
incidence
oo
Accurate
reading
Free
Mount
Random
Incidence
Adaptor
Accurate
reading
820331
Fig. 3.4.
Flow
chart
for
use
of
the
Random
Incidence
Adaptor
regard-
ing
standards
and
type
of
sound
field
IEC
Standards:
When
performing
measurements
requiring
the use
of
a
sound
level
meter
to
IEC
stan-
dards
the
Random Incidence
Adaptor
DZ 9566 should NOT be
mounted
on
the
microphone.
The
sound
level
meter
should
be
pointed
directly
at
the
source
if
a
free
field
condition
is
assumed
to
exist
(Fig.3.S). In a
diffuse
field the sound level
meter
may
be
orientated
in
any
oirection.
Fig. 3.5.
Measurements
to lEG
Standards
in a free
sound
field
ANSI
Standards:
When
performing
measurements
requ1rmg the use
of
a
sound
level
meter
to
ANSI
standards,
the
"free
field"
microphone's
characteristics
should
be
adapted
to
a
linear
random
incidence
response
by
mounting
the
Random
Incidence
Adaptor
DZ 9566.
This
applies
for
measurements
in all
types
of
sound field.
In a
truly
diffuse
field,
the
sound
level
meter
can be
oriented
in
any
direction.
Under
ideal
free
field
conditions
optimum
response
is
obtained
by
orientating
the
sound
level
meter
as
shown
in Fig.3.6.
Fig. 3.6.
Measurement
to
ANSI
Standards
in a free
sound
field
Measurements
not
requiring
the
use of an IEC or
ANSI
sound
level
meter:
Measuring
with
a
free
field
microphone
in a
diffuse
field,
or
measuring
with
a
linear
random
incidence
response
microphone
in a
free
field
results
in
small
innaccuracies
in
the
values
obtained.
More
accurate
results will
be
obtained
by
selecting
the
appropriate
m~crophone
frequency
response
to
suit
the
type
of
sound
field.
Consequently,
when
adherence
to IEC
or
ANSI
Sound
Level
Meter
Standards
is
not
required,
the
Random
Incidence
Adaptor
DZ 9566
should
not
be
mounted
on
the
micro-
phone
under
free
field
conditions,
and the
meter
should
be
pointed
directly
at
the
sound
source
during
measurements.
A
free
field
condition
can
generally
be
assumed
for
outdoor
measurements
or
in
absorbent
rooms.
13
For
measurements
in a
diffuse
field,
the
Random
Incidence
Adaptor
DZ 9566
should
be
mounted
on
the
microphone,
and the
meter
may
be
oriented
in
any
direction
in
the
diffuse
field.
A
diffuse
field can
generally
be
assumed
for
indoor
measurements
or
in
reverbera-
tion
rooms.
3.5.3.
Leq
and
SEL
Measurements
1.
Carry
out
the
calibration
check
before
commencing
with
a
measurement:
2.
Set
the
controls
on the
Sound
Level
Meter
as
follows:
FUNCTION:
Leq
or
SEL
Leq
RANGE: in
order
to
include
the
expected
value
MODE:
"Run"
POWER:
"On"
3.
To
begin
measurement,
press
RESET.
The
Leq
or
SEL value
measured
can
be
read
directly
from
the
display
which
is
updated
twice
per
second
while the
measurement
is running.
Alternatively
the
measurement
can
be
interrupted
by
setting
the
MODE
switch
to
"Pause".
The
"A"
displayed
indicates
that
A-weighting
is applied.
If
an
input
overload
occurs,
the
sign
"•"
appears
(held
continuously)
and the
reading
may
be
incorrect.
Switch
Leq
RANGE
to
a
higher
range.
If
the
input
signal
is
underrange
the
sign
"'f'"
appears.
If
it
is
displayed
too
often,
switch
Leq
RANGE
to
a
lower
position.
Switching
between
measuring
ranges
automatically
resets
the
instrument.
The
Leq
measurement
duration
for
periods
shorter
than 2,77
hours
can
be
obtained
by
substracting
the
measured
Leq
from
the
SEL value and using
the
conversion
table
at
the
back
of
the
instrument.
SEL is
obtained
by
setting
FUNCTION
to
"SEL".
See Fig.3.7.
The
Leq
value
displayed
for
measurements
over
a
period
of
more
than 2,77
hours
will
be
incorrect
and a
"*"
will
appear
on
the
display.
However,
knowing
the
measurement
duration,
the
correct
Leq
value can
be
obtained
from
the SEL
indication
using
the
conversion
table
at
the
back
of
the
instrument.
The
measurement
period
for
an SEL
measurement
is
only
limited
by
the
battery
life.
Note:
It
is
possible
to
switch
between
"Leq"
and
"SEL"
during
a
measurement
without
loosing
the
results. When
measuring
low
levels
it
is
recommended
to
set
the
MODE
switch
to
"Pause"
before
switching
between
"Leq"
and
"SEL",
as the
clicking
noise
from
the
switch
may
introduce
an
error.
This is
irrelevant
when
measuring
higher
levels.
3.5.4.
Max
Hold
"Fast"
or
"Slow"
Measurements
14
1.
Carry
out
the
calibration
check
before
commencing
with
a
measurement.
2.
Set
the
controls
on the
Sound
Level
Meter
as
follows:
FUNCTION:
Max
Hold
"Fast"
or
"Slow"
Leq
RANGE:
MODE:
POWER:
to
include
the
expected
value
"Run"
"On"
This manual suits for next models
1
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