BRUEL & KJAER 1616 User manual

1 /3 Octave Filter Set
Type 1616
A portable third-octave filter set which satisfies IEC Rec-
ommendation
225, ANSI S1 .11-1966 class Ill and DIN
45 652 . It is designed for operation with and attachment
to the B & K Sound Level Meters Types 2203 and 2209.
Filter centre frequencies 20Hz to 40kHz, plus a "Lin-
ear" mode 22,4 Hz to 40kHz.
Provision is made for semi-automatic frequency analysis
in conjunction with the B & K Level Recorder Type
2306 .
BrUel & Kjcer
,,®
Oo•®
BrUel &Kjaer
Copenho~en
1616

BR OEL & KJ)ER instruments cover the whole field of sound and vibration measurements. The main groups are:
ACOUSTICAL MEASUREMENTS
Condenser Microphones
Piezoelectric Microphones
Microphone Preamplifiers
Hydrophones
Sound Level Meters
Precision Sound Level Meters
Impulse Sound Level Meters
Noise Dose Meters
Noise Level Analyzers
Standing Wave Apparatus
Calibration Equipment
Reverberation Processors
Sound Sources
ACOUSTICAL RESPONSE TESTING
Sine Generators
Random Noise Generators
Sine -Random Generators
Artificial Voices
Artificial Ears
Artificial Mastoids
Hearing Aid Test Boxes
Audiometer Calibrators
Telephone
Measuring Equipment
Audio Reproduction Test Equipment
Tapping Machines
Turntables
VIBRATION MEASUREMENTS
Accelerometers
Force Transducers
Impedance Heads
Accelerometer Preamplifiers
Vibration Meters
Accelerometer Calibrators
Magnetic Transducers
Capacitive Transducers
Complex Modulus Apparatus
Bump Recorders
VIBRATION TESTING
Exciter Controls - Sine
Exciter Controls - Sine -Random
Exciter Equalizers, Random or Shock
Exciters
Power
Amplifiers
Programmer Units
Stroboscopes
STRAIN MEASUREMENTS
Strain Gauge Apparatus
Multipoint Selectors
MEASUREMENT AND ANALYSIS
Voltmeters
Phase Meters
Deviation Bridges
Measuring Amplifiers
Band-Pass Filter Sets
Frequency Analyzers
Real Time Analyzers
Heterodyne Filters and Analyzers
Distortion Measuring Equipment
Psophometers
Statistical Distribution Analyzers
Tracking Filters
RECORDING
Level Recorders
Frequency Response Tracers
Tape Recorders
Alphanumeric Printers
Digital Event Recorders
DIGITAL EQUIPMENT
Computers
Tape Punchers
Tape Readers
Bri.iel & Kjcer
DK-2850 NJERUM, DENMARK · Telephone: + 45 2 80 05 00 · TELEX: 37316 bruka dk
1I 3 Octave Filter Set
Type 1616
A portable third-octave filter set which satisfies IEC Rec-
ommendation
225, ANSI S1 .11-1966 class Ill and DIN
45 652. It is designed for operation with and attachment
to the B & K Sound Level Meters Types 2203 and 2209.
Filter centre frequencies 20Hz to 40kHz, plus a "Lin-
ear" mode 22,4 Hz to 40kHz.
Provision is made for semi-automatic frequency analysis
in conjunction with the B & K Level Recorder Type
2306 .
Bri.iel & Kjcer
'·®
o~@
Briiel &Kjcsr
Copenha!jen
1616
®

1/3 OCTAVE FILTER SET
TYPE 1616
Applicable to instruments from
serial No.
605 532
May 1 976

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS (PRODUCT DATA) ..... ........................................ .... 1
2. CONTROLS ................................................................................ ...................... .................... 5
3. OPERATION ..................... .................................... ................................................................ 7
3.1. REPLACEMENT OF BAITERIES ................................................................. 7
3.2. MOUNTING ON THE SOUND LEVEL METER ............................................... 7
3.3. USE WITH THE PRECISION SOUND LEVEL METER TYPE 2203 .................... 8
Sound Measurements ....................................................................... ·•...... 8
Vibration Measurements .......................................................................... 9
3.4. USE WITH THE IMPULSE PRECISION SOUND LEVEL METER
TYPE 2209 ......................................................................................... .. .. 10
Sound Measurements ...................................................................... .. ...... 10
Vibration Measurements .......................................................................... 11
3.5. USE WITH THE LEVEL RECORDER TYPE 2306 ............... ; ........................... 12
System Set-up .................................................................................... .. .. 12
Synchronization ...................................................................................... 13
Frequency Analysis ...........................................................................
.. .... 14
3.6. RMS MEASUREMENTS AND STATISTICAL ACCURACY ............................... 14
4. DESCRIPTION ..................................................................................................................... 17
4.1 . GENERAL ............................................................................................... 17
4.2. INPUT .................................................................................................... 17
4.3. THIRD-OCTAVE FILTERS .......................................................................... 18
General .................................................................................................. 18
Filter Design ........................................................................................... 20
Filter Transient Response . .. .. .................... .. . .. . .. . .. . .. ... .. ..... .. .... .. .. .. .. .. .. .... .. 22
4.4. HIGH-PASS FILTER ................................................................................. 23
4.5. OUTPUT AMPLIFIER ................................................................................ 24
4.6. POWER SUPPLY ..................................................................................... 24

FEATURES 1613:
• 11 octave filters in
accordance
with IEC, DIN
and ANSI Class II
requirements
• Centre frequencies from
31,5 Hz to 31,5 kHz,
frequency range from
22Hz to 45kHz
• 0 dB nominal filter
attenuation, individually
adjustable 0 to 50 dB
• Facility available for
synchronization with Level
Recorder Type 2306
FEATURES 1616:
• 34 third-octave filters in
accordance
with IEC, DIN
and ANSI Class Ill
requirer:1ents
•
Centre frequencies from
20Hz to 40kHz, frequency
range from 18Hz to
44kHz
• 0 dB nominal filter
attenuation
• Push-button filter shift and
filter-shift indicator lamp
for semi-automatic
analysis with Level
Recorder Type 2306
• Battery monitoring meter
USES:
In
combination with Sound
Level Meters Types 2203
and 2209:
• Noise and vibration
analysis
• Attenuation of background
noise
16-119
types 161 3 and 161 6
Octave Filter Set and
Third-Octave Filter
Set
On O ff
1111
Weighting Sw itch
12 5 @)
63 f)
Frequency Hz
Octave Filter Set
. 16000
.31500
Br ue l & Kjcer s ~ Type 1613
C.,.n.ogen ....... K
• Distortion measurements
• Calibration of audiometers
• Loudness evaluation in
accordance with ISO
R 532 (Stevens and
Zwicker)
• Noise and vibration
checking to octave and
third-octave limiting curves
• Building-acoustic
measurements
• Sound-power
measurements on
machines
Additional use for Type
1616:
• External filter for Vibration
Meters Types 251 0 and
2511
-
BrUe l &Kjaer A.&._, Type 1616
Copenhog•n ~ "'
1 /3 Octave Filter Set
The Octave Filter Set Type 161 3
and the 1/ 3 Octave Filter Set Type
1616 fit the Precision and Impulse
Precision Sound Level Meters Types
2203 and 2209 both mechanically
and electrically to form a compact
portable unit for the analysis of
noise and vibration , as shown in
Fig.1.
Impulse
Precision
Sound Level
Meter 2209
1/3 Octave
Filter Set
1616
Precision
Sound Level
Meter 2203
Octave
Filter Set
1613
16
Fig.1. Combination possibilities between Fil-
ter Sets and Sound Level Meters

Description
General
The overall frequency range of
both filter sets covers the entire au-
dio-frequency range. The centre fre-
quencies are arranged according to
the preferred frequencies of ISO
R 266, DIN 45 401, and ANSI S 1 .6-
1 960, and the filters may be
switched in successively by means
of the selector switch, to perform a
frequency analysis. The level in
each frequency band may be noted
in a measurement report or plotted
on graph paper,
or the analysis can
be recorded on
the portable Level
Recorder Type
2306. It is possible
to connect each filter set to the
2306 to allow synchronized semi-
automatic frequency analyses to be
made, as explained
later in the text .
Octave Filter Set Type 1613
Type 1 61 3 contains 11 passive
octave
filters with centre frequen-
cies from 31,5 Hz to 31,5 kHz. In
combination with a Sound Level Me-
ter, each octave filter satisfies the
requirements of IEC Recommenda-
tion 225, DIN 45 651, and ANSI
S1 . 11-1966 Class II , see Fig.2.
The total
frequency coverage is
from 22Hz to 45kHz as can be
seen in Fig.3. A
linear position is
also available covering
the fre-
quency range from 3Hz to 40kHz.
The signal from each filter may
be individually attenuated from 0 to
50 dB by screwdriver-adjusted pot-
entiometers. These can be reached
through small holes in the front
0
dB
10
20
30
40
50
60
70
80
Attenuation
A
r
IEC 225 (1966) ij!
01 N 4~,§_51
1
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7 v I
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1/ j I
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tf
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ANSI 51 . 11 -1966
'
Class 11-
~1
I
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vv
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Typical o~})
~
Filter in
Type 1
161T 1
0.1 0.2 0.3 0.50 .7 1 .5 2 3 4 5 7 10
Frequency Relative to Centre Frequency f/fm
172485
Fig.2. Typical octave filter characteristics of
Type 1613 with IEC, DIN and ANSI li-
mitation curves drawn in
2
cover of the instrument. It is thus
possible to obtain filter characteris-
tics that match individual noise-limit
requirements or, for example, that
match the A-weighting curve. An ex-
ample of use
of the weighting poten-
tiometers is shown in Fig.4. The 0
to 50 dB attenuation is also avail-
able
in the linear range. All poten-
tiometers can be switched in or out
simultaneously by a front-panel
switch.
The Octave Filter Set should be
fed
from a signal source with an im-
pedance less than 25 n, and the
load impedance should be 146 kO
in parallel with from 40 to 60 pF .
This
means that the 1 61 3 should
not be used as an external filter for
the Vibration Meters Types 2 51 0
and 2511, or for driving the Power
Amplifier Type 2706, without sui-
table buffer stages.
Correct
terminating conditions are
automatically fulfilled when the
1 61 3 ·is connected to a Sound Lev-
el
Meter Type 2203 or 2209. The
electrical connection is provided by
the screened connecting bar JP
0400 supplied with the 1 61 3 as a
standard accessory.
Low-capacitance cables are avail-
able
for connecting the 1 61 3 to
other B & K instruments. AO 0034
is 0,6 m long and has a capacitance
of approximately 20 pF. The capaci-
tive component of the input imped-
ance of the connected instrument
should therefore not exceed 40 pF.
If it does, there is a risk of the high-
frequency filters exceeding their tol-
erance limits. Some older types of
B & K instruments have an input im-
pedance of 1 ,2 MO in parallel with
40 pF at the external-filter socket,
and in
such combinations the AO
0034 is used at the filter input
while the 0,6 m cable AO 0035
containing a 1 62 kO shunt resist-
ance in the plug, should be used at
the output.
Bruel & Kj110r Bruel & Kj110r Bruel & Kj110r
ODOOOODDDDDDDDDDDOOOOOOOODOOODODODODODDDDDODOODOO
Bruel& Kjcer Potent io meter Range : --dB Rectifier :-- lower lim . Freq .:- Hz Wr. Speed :- mm / sec . Paper Speed: - mm / sec .
Copenhagen 50 2 5
10 7
... d8d
B dB d
40 20 8 6
easuring Obj .: 10
dB
5 6 4
0 4 3
2 1
10 20 Hz 50 100
200
500 1000
2000
5000
10000 20000 400000 A B Cion. O
QP 1124
Multiply Frequency Scale by Zero Level:
1612 / 2112
A B C 750282
Fig.3. Frequency characteristics of the 11 octave filters in Type 1613
Bruel & Kj110r Bruel & Kj110r Bruel & Kj110r
DDDDDDDDDDDDDDDDDOOOOOOOOOODOOODODDDOOOOODDDDODOD
ruel& Kjcer Potentiometer Range·--dB Rectifier · --Lower lim . Freq : -Hz Wr Speed ·- mm / sec Paper Speed · mm / sec .
·-
10 7
Copenhagen 50 25 5
+ dBdB
dBd
40 20
8 6
easuring Obj .:
~10dB
---3015
6 4
---2010
4 3
2 1
Rec . No .:
Date __
Sign .: __ 0
10 20
Hz
50
100 200 500 1000 '2000 I 5000
10 00 20000 4C10 OOD
A B C lin .
QP 1124
Multiply Frequency Scale by
Zero Level: 161212112
A B C 750281
Fig.4. Example of use of the weighting potentiometers in Type 1613

Precision
Sound
Level
Meter
2203
or 2209
Octave
Filter Set
1613
Fig.5. Portable set-up for semi-automatic oc-
tave analysis and recording
When the 1613 is connected to
the 2306 with cable AQ 014 7
which has a built-in switch and
green lamp,
the 2306 recording
paper
wi II stop each time its red oc-
tave
filter-shift lamp lights, and the
green lamp in the cable's switch
will light. The filter is then ad-
vanced
manualfy, and the switch de-
pressed,
starting the paper again.
Another octave is recorded, and the
process is repeated. The set-up and
an example
of analysis are shown
in Figs.5 and 6 respectively.
1/3 Octave Filter Set Type 1616
Type 1 61 6 contains 34 active
third-octave filters with centre fre-
quencies from 20Hz to 40kHz.
Each filter fulfils in itself the require-
ments of IEC Recommendation
225, DIN 45 652, and ANSI S1. 11-
1966 Class Ill, see Fig.7. The total
frequency coverage is from 18 Hz to
44kHz as can be seen in Fig.8.
A
linear position is available
covering the frequency range from
22,4 Hz to 40kHz . A 22,4 Hz high-
pass fiIter
with a slope of
30 dB/octave below pass-band is in-
cluded to suppress disturbance from
0
dB
10
20
30
40
50
60
70
80
Attenuation
[)
I
v ~
v
,j
/
1/
I~
J
l/v
I~
/ I
I
IV
--
-V
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IEC
1
22~ ( ~ 96~)
1:7
DIN,45t 5J2 I -
~
\I \ANSI 51.11-1966
Class Ill
I
~~
r\
t7
\v
1\
[·,
f\,
['..~
' \
Typical _.I\'
B&K 1
1/3 Octavj ' \
Filter i\
-- -
0.1 0.2 0.3 0. 50 .7 1 1.5 2 3 4 57 10
Frequency Relative to Centre Frequency f/fm
172486
Fig. 7. Typical third-octave filter characteris-
tic of Type 1616 with IEC, DIN, and
ANSI limitation curves drawn in
Bruel & Kjm r
Bruel & Kja>r
Br uel & Kja>r
D DO D D ODODDD D D DO DDDDDD DD DD DD DDD ODD OOOO O OOOO OD ODODOD
Bri.iei&Kjaer Potentiometer Range : __§Q_dB Rectifier : -Lower Lim Freq .:~ Hz Wr Speed : ~mm / sec Paper Speed: 0,3 mm /sec.
Copotnh • gen 502ll~i~~~~~~~~~~~~~i~~~~~~~~~~i1
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Measuring Obj .
Ge ar Tr ain 30 15
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1
5
~
1 3
20 1
a nd 2306
Rec. N~1 5 2 15
Dat e:
Sign .:_
0 0 0 0
10 20 Hz 50 100 200 Hz 500 1000 2000 Hz 5000 10000 20000 40000 D A B C Lm.
QP 0124
Multiply Freq. Scale by Zero Level: (1 612 / 211 2) A B C Lin. 750 1 85
Fig.6. Octave analysis of gear train noise using the set- up in Fig.5
- Bruel & Kja>r Bruel & Kja>r Bruel & Kja>r
DDOOODOOODODDODOODDDDDOOODODOOOOODO O OD DO D D DDDDD
IBruel&Kjaer Potentiometer Range :-- dB Rectifier : --Lower Lim . Freq .: -Hz Wr . Speed :- mm /sec. Paper Speed: - mm / , .,c
Copenhagen
•
~easur i 1 Obj .
Rec . No .:
Date
Sign .:
loP 1124
1( f5
20 Hz 50 100
Multiply Frequency Scale by
I "~
200 5m
)0 ·21 O(
sc 10000 20000 400000 A 8 C lin~
Zero
1612 / 2112 A B C 750283
Fig.8. Frequency characteristics of the 34 third-octave filters in Type 1616
low-frequency signals. To damp un-
wanted high-frequency compo-
nents, a
40kHz low-pass filter is
also included. It is designed for lin-
ear phase response giving a smooth
frequency cut-off and impulse or
transient response without over-
shoot. This last
feature is of special
importance when impulse measure-
ments are made with the 1 61 6/
2209 combination . Then distur-
bances from low-frequency compo-
nents are avoided at the same time
as an overshoot-free high-frequency
cut-off is maintained.
As the 1 61 6 has a buffer stage
in both
input and output, it is less
critical
than the 1 61 3 regarding in-
terconnection with other instru-
ments. It is well suited, for exam-
ple, as an external filter for the Vi-
bration Meters Types 251 0 and
2511, and it can drive the Power
Amplifier Type 2706. Loading the
output with too small a resistive
load, however, will cause a low-fre-
quency cut-off determined by a
2,2~JF capacitance in the 1 61 6 out-
put stage and the resistive load. A
load of 15 kO will only cause an at-
tenuation of approximately 0,25 dB
at
20Hz.*
Electrical connection between the
1 61 6 and a Sound Level Meter
Type 2203 or 2209 is provided by
the screened connecting bar JP
0400 supplied as a standard acces-
sory
with the 1 61 6. Cables are
available for connecting the 1 61 6
to other instruments . The 1 ,2m
cable AO 0007 and the 0,6 m AO
0034 are fitted with a standard
B & K plug
while the 1 ,2m AO
0116 is fitted with a BNC plug.
When the 1 61 6 (after serial No.
605 532) is connected to the 2306
with cable AQ 0148, the 2306 re-
cording paper
will stop each time its
red third-octave
filter-shift lamp
lights, and
the green lamp on the
front of the 1 61 6 will light. When
the push button on the side of the
1 61 6 is depressed, the fiIter is auto-
matically advanced, and its output
is short-circuited to prevent switch-
ing transients being recorded; the
2306 recording paper is started si-
multaneously by the same push but-
ton. Another third octave is re-
corded, and
the process is repeated.
The
set-up and an example of analy-
sis are shown in Figs.9 and 10 re-
spectively.
* 161 6s with serial No . below 541 21 8 have
0.47 JJF in the output stage causing an at-
tenuation of approx . 3,3 dB at 20Hz when
loaded with 15 kO. Modification to the later
standard is easy
3

Precision
Sound
Level
Meter
2203
or 2209
1/3
Octave
Filter Set
1616
Portable Level Recorder
2306
760582
Fig.9. Portable set-up for semi-automatic
third-octave analysis and recording
[Rec. N JL _ 1C
Date :
Si gn .:
Qp 0124
lz
15
Multiply Freq . Scale by
2 15
10 IO )00 40000 D A B C Lin.
(161212112) A B C Lin. 750258
Fig.10. Third-octave analysis of gear train noise made with the set-up in Fig.9
Specifications 161 3 and 161 6
Filter Set Type
1613, Octave
1616, Third-Octave
Frequency Range
Selective 22Hz to 45kHz
18 Hz to 44kHz
Linear 3Hz to 40kHz
22.4 Hz to 40kHz
Screwdriver adjustment of attenuation
0 to High-pass
filter 22.4 Hz, slope
below pass-
50 dB
band 30 dB/octave
Low -pass filter 40kHz
Band-Pass Filters 11 passive 6-pole Chebishev octave filters
34 active 6-pole Butterworth
third-octave
til-
ters
In accordance with
IEC R 225 - 1966 , DIN 45 651 and
IEC R 225 -1 966, DIN 45 652 and
ANSI S1 . 11-1966, Class II
ANSI S1. 11 - 1966, Class Ill
Centre Frequencies
31 , 5Hzto 31,5kHz
20Hz to 40kHz
Attenuation at centre frequency
0 dB ± 0,5 dB or screwdriver adjustment
OdB ±0,5dB
between 0 dB and 50 dB
Peak-to-valley ripple < 1, 5dB
< 0,5 dB
Attenuation outside pass band See Fig.2 See Fig.7
Filter Shift
Rotary switch
Rotary switch and push button, output short-
Green lamp in cable
AQ 014 7 indicates time circuited during switching with push button
for filter switching * Green lamp indicates time
for filter switching*
Remote Control
Remote control of Level Recorder Type 2306
Remote control of Level Recorder Type
2306
via switch in cable AQ 014 7 via push
button on 1 61 6
Input Impedance
-101<0 ± 5%, max. 1 OV DC at input
Input Terminating Impedance ~ 250
-
Input Voltage
Max . 1V RMS
Max . 2V Peak
Output Impedance
-<
50 in series with 2,2J1F
Output Terminating Impedance 146 kO / / 40 to 60pF
;;;, 15 kO (approx.
0, 25 dB attenuation at 20Hz
with 15 kO load)
Inherent Noise Not applicable < 200J1V RMS
Magnetic Sensitivity (50 Hz) Approx.
200 mV at output for
Approx. 1 mV at output for
1
00 A/ m field strength 1
00 A/ m field strength
Operating Temperature -20 to+ 50 °C (-4 to+ 122 ° F)
Influence ofTemperature
< 0,5 dB
Influence of Humidity < 0,5 dB for 0 to 90% relative humidity
Batteries
None 3 x 1,5 V size D cells (QB
0004)
(Type R 20 in IEC Publ. 86 -2)
Battery life Not applicable 8 hours
for normal operation
Dimensions
Length 155 mm (6 ,1 in)- Width 120 mm (4,7 in) -Height 94 mm (3 ,7 in)
Weight 2,5 kg (5 ,51b) 1,9 kg (4,21b) including batteries
Accessories Included
1 Electrical Connecting Bar JP 0400
1 Electrical Connecting Bar JP 0400
2 Screened Plugs JP 0006
2 Screened Plugs JP 0006
1 Mi niature Screwdriver QA 0001
1 Plug JP 0406
1 Screwdriver QA 0027
3 Batteries QB 0004
Accessories Available 2m control cable for 2306 AQ 0147
1,2 m control cable for 2306 AQ 0148
0,6 m low-capacitance cable AO 0034
1,2 m cable with B & K plug AO 0007
0,6 m low - ca~acitance cable with
1,2 m cable with BNC plug AO 0116
1 62 kO shunt resistance AO 0035
0, 6 m low-capacitance cable AO 0034
NOTE: To couple the 1616 to a 2203 with serial No. 424272 and earlier, a new bottom plate for the 2203, DD 0135, must be ordered separately.
* Level Recorders Type
2306 before serial No. 576700 need a minor modification to make green indicator lamps work.

POWER:
METER:
IN and OUT:
SYNCHRONIZATION:
2. CONTROLS
Bri.iel & Kjaer 8 ~
Co p enhogen ~ ~
Type 1616
1/3 Octave Filter Set
Fig. 2. 1. Front view of 1616
On/Off switch for connecting internal battery power to instrument.
A built-in meter for battery check. Green and red areas indicate suffi-
cient and insufficient battery condition. For changing batteries, see
§ 3.1.
These sockets are for connection to the Sound Levef Meter EXTERNAL
FILTER sockets via the Connection Bar JP 0400 or to other equipment
via cables AO 0007. The sockets accept the B & K coaxial plug JP
0006.
Input impedance at the IN socket is 10 kO, the maximum input voltage
IJeing 2 V peak.
Max. DC voltage at input: 1OV. Output impedance at
the OUT socket is less than 50 in series with 2,2J.LF. The socket
should not be loaded by less than 15 kO.
Socket for connection to the EXTERNAL POWER/REMOTE CONTROL
socket of the B & K Level Recorder Type 2306, permitting semi-auto-
matic frequency analyses to be recorded on frequency-calibrated
paper.
See§ 3.5. The socket accepts the B & K plug JP 0406.
5

FILTER SWITCH:
FILTER SHIFT:
FILTER SHIFT LED:
6
A 35-position switch for selection of the required filter . Filter centre
frequencies are indicated around
the switch. A "Lin." position
(22,4 Hz to 40kHz} is also provided.
When this push button is depressed, the FILTER SWITCH is mechani-
cally stepped by one third octave and the output signal is suppressed
to avoid
switching transients. The push button also controls the paper
start
of the Level Recorder Type 2306 by opening a contact at the SYN-
CHRONIZATION socket.
This green lamp is controlled by
the Level Recorder Type 2306 when
connected to the 1616 by cable AQ 0148. It lights at the same time
as the red 1 /3-octave FILTER SHIFT lamp on the 2306 is lit to indi-
cate
when to switch the fiIter.

3. OPERATION
3.1. REPLACEMENT OF BATTERIES
Before using the 161 6, the battery condition should be checked. Set the POWER switch
to "On" . The needle of the built-in meter should deflect into the green area. If not, the
batteries should be replaced. The batteries are accessible by sliding off the cover at the
rear of the i nstrument (Fig.3.1 ). Take care to observe the correct polarity when inserting
the
new batteries.
Fig .3.1. Rear view of 1616 with battery cover removed
3.2. MOUNTING ON THE SOUND LEVEL METER
The 1 61 6 can be directly attached to either Precision Sound Level Meter Type 2203 or
Impulse Precision Sound Level Meter Type 2209. For a 2203 with serial No. 424272
and earlier, a new bottom plate, part No. DD 0135, must be ordered separately to re-
place the original bottom plate.
The 1
61 6 screws directly onto the Sound Level Meter using the large finger screw
(Fig.2.1). Electrical connection is then established by plugging in the Connection Bar JP
0400 supplied with the 1616. The portable analyzers thus obtained are shown in
Fig.3.2 and 3.3 .
If desired, move the leather carrying handle of the Sound Level Meter to give a correct
7

Fig .3. 2. The 1616 mounted
on the Precision
Sound Level Meter
Type 2203
Fig.3.3. The 1616 mounted
on the Impulse Preci-
sion Sound Level Me-
ter Type 2209
balance of the combined instruments. Note that bushes for the handle's screws are on
both sides of the instrument.
Note: when the 1 61 6 is fitted on the 2203, the Sound Level Meter batteries can only
be changed by removing the Filter Set.
3.3. USE WITH PRECISION SOUND LEVEL METER TYPE 2203
3.3.1. Sound Measurements
8
1. Calibrate the Sound Level Meter as described in its Instruction Manual.
2. Set the POWER switch of 161 6 to "On" and check battery condition . The needle of
the built-in meter should deflect into the green area. If not, change batteries as indi-
cated in § 3.1.
3. Set the METER SWITCH of 2203 to one of the "Lin ." positions ("Fast" or "Slow" as
required).
4. Hold the instrument steadily as far away from the body as possible (preferably use a
tripod or other firm non-interfering support . The microphone should be at least 1
metre away from the observer's body) with the microphone directed towards the
measuring object.
5.
With the transparent OUTPUT ATTENUATOR knob in its fully clockwise pos1t1on,
turn the black INPUT ATIENUATOR knob until a meter deflection in the top 2/3 of
the scale is obtained. If this is not possible, the transparent knob may also be used.
However, the transparent knob should be kept as far clockwise as possible in order
to maintain the optimum signal-to-noise ratio .

6. Set the METER SWITCH of 2203 to one of the "Ext. Filt." positions ("Fast" or
"Slow", as required).
7. Select
the desired fiIter on the 1 61 6 by setting the FILTER SWITCH to the required
position. If switching transients are to be avoided, this may be done using the FIL-
TER SHIFT push button to step the FILTER SWITCH to the required position.
8.
If the meter indicates less than 0 dB, increase sensitivity using the transparent OUT-
PUT ATTENUATOR
on 2203.
9. The measured sound pressure level in the third-octave band selected is the sum of
the meter reading and the number in the red lines on the transparent knob.
3.3.2. Vibration Measurements
1. Calibrate the 2203 as described in its Instruction Manual.
2. Set the POWER SWITCH of 1 616 to "On" and check battery condition. The needle
of the built-in meter should deflect into the green area. If not, change batteries as in-
dicated in§ 3.1.
3. Mount the accelerometer using one of the methods described in its Instruction Man-
ual, taking care to avoid cable whip. For measurements of velocity or displacement,
use can be made of the Integrator ZR 0020 (See Fig.3.4).
'§f.-
~ -- -.,~.. .,., ......... ~
,.
'it
Fig.3.4 . Integrator ZR 0020
4. Set the METER SWITCH of 2203 to one of the "Lin." positions ("Fast" or "Slow" as
required).
5. Hold
the instrument as far as possible from the vibration environment and other un-
desirable influences.
6. With the transparent OUTPUT ATTENUATOR knob in its fully clockwise position,
turn the black INPUT ATIENUATOR knob until a meter deflection in the top 2/3 of
the scale is obtained. If this is not possible, the transparent knob may also be used.
However, the transparent knob should be kept as far clockwise as possible in order
to maintain the optimum signal-to-noise ratio.
7. Set
the METER SWITCH of 2203 to one of the "Ext. Filt." positions ("Fast" or
"Slow" as required).
8. Select
the desired fiIter on the 1 61 6 by setting the FIILTER SWITCH to be required
position. If switching transients are to be avoided, this may be done using the FIL-
TER SHIFT push button to step the FILTER SWITCH to the required position.
9. If
the meter indicates less than 0 dB, increase sensitivity using the transparent OUT-
PUT ATTENUATOR
on 2203.
9

·$'
;l#
.. ~
,...,
iJ
_gf
"""C
... -
~~
-i~
? '&
~ - ~
.,'1:.«
"'· 0~
.,.$'
I' dB- vibration unit converter
QH0001
265672
Fig. 3.5. The Slide Rule set to an accelerometer sensitivity of
50 mV/g and an instrument reading of 60 dB
1 0. Read the vibration level in dB indicated by the meter.
11. Set the Slide Rule QH 0001 supplied with the Integrator to the correct accelerome-
ter sensitivity (mV/g). An example is given in Fig.3 .5.
12. Set the cursor to the number of dB read on the 2203 and read off the correspond-
ing RMS acceleration, velocity
or displacement.
Note: the slide rule cannot be used for conversion of for example acceleration to veloc-
ity. Each scale
must only be used in connection with the appropriate setting of
"Ace.", "Vel." or "Disp." on the Integrator ZR 0020.
3.4. USE WITH THE IMPULSE PRECISION SOUND LEVEL METER TYPE 2209
3.4.1. Sound Measurements
10
1. Calibrate the 2209 as described in its Instruction Manual.
2. Set the POWER SWITCH of 1 61 6 to "On" and check battery condition. The needle
of the built-in meter should deflect into the green area. If not, change batteries as in-
dicated in§ 3.1.
3. Set the controls of 2209 to:
WEIGHTING NETWORK
METER SWITCH
"Lin."
as required
4. Hold the instrument steadily as far away from the body as possible (preferably use a

tripod or other firm non-interfering support. The microphone should be at least 1 m
away from the observer's body) with the microphone directed towards the measur-
ing object.
5.
With the transparent OUTPUT ATTENUATOR knob in its fully clockwise position,
turn the black INPUT ATIENUATOR knob until a meter deflection in the top 2/3 of
the scale is obtained. If this is not possible, the transparent knob may also be used.
However,
it should be kept as far clockwise as possible in order to maintain the opti-
mum signal-to-noise ratio.
If the OVERLOAD INPUT lamp flashes, the black INPUT ATIENUATOR knob should
be switched anti-clockwise until the overload is removed. The meter deflection
should then be restored by
turning the transparent knob anticlockwise.
6. Set the WEIGHTING NETWORK switch of 2209 to "Ext. Filter".
7. Select the desired filter on the 1 61 6 by setting the FILTER SWITCH to the required
position. If
switching transients are to be avoided, this may be done using the FIL-
TER SHIFT push button to step the FILTER SWITCH to the required position.
8. If the meter indicates less
than 0 dB, increase sensitivity using the transparent
knob.
If the OVERLOAD OUTPUT lamp flashes, turn the transparent OUTPUT ATTENUA-
TOR clockwise until the overload is removed. If the overload cannot be removed
while retaining a meter deflection, any reading taken will be lower than the true sig-
nal level and the overload indication should be noted with the results.
9. The measured sound pressure level in the third-octave band selected is the sum of
the meter reading and the number which appears between the two red lines on the
transparent knob.
3.4.2. Vibration Measurements
1. Calibrate the 2209 as described in its Instruction Manual.
2. Set the POWER SWITCH of 1 61 6 to "On" and check battery condition. The needle
of the built-in meter should deflect into the green area. If not, change batteries as in-
dicated in§ 3.1.
3. Mount the accelerometer using one of the methods described in its Instruction Man-
ual, taking care to avoid cable whip. For measurements of velocity or displacement,
use can be made of the Integrator ZR 0020 (See Fig.3.4).
4. Set
the controls of 2209 to:
WEIGHTING NETWORK
METER SWITCH
"Lin."
as desired
5. Hold the
instrument as far as possible from the vibration environment and other un-
desirable influences.
6. With the transparent OUTPUT ATTENUATOR knob in its fully clockwise position,
turn the black INPUT ATIENUATOR until a meter deflection in the top 2/3 of the
scale is obtained. If this is not possible, the transparent knob may also be used.
However,
the transparent knob should be kept as far clockwise as possible in order
to
maintain the optimum signal-to-noise ratio.
11

If the OVERLOAD INPUT lamp flashes, the black INPUT ATIENUATOR knob should
be switched anticlockwise until the overload is removed. The meter deflection
should then be restored by turning the transparent knob anticlockwise .
7.
Set the WEIGHTING NETWORK switch of 2209 to "Ext . Filter".
8. Select the desired filter on the 1616 by setting the FILTER SWITCH to the required
position. If switching transients are to be avoided, this may be done using the FIL-
TER SHIFT push button to step the FILTER SWITCH to the required position.
9. If the meter deflection is less than 1/ 3 of full scale, increase sensitivity using the
transparent knob.
If the OVERLOAD OUTPUT lamp flashes, turn the transparent OUTPUT A TIENUA-
TOR knob until the overload is removed. If the overload cannot be removed while re-
taining a meter deflection, any reading taken will be lower than the true signal level
and
the overload indication should be noted with the results.
10 . The RMS vibration level in the third-octave band selected is read on the meter. The
level corresponding to full scale deflection is indicated by the number which appears
between the two red lines on the transparent knob.
3.5. USE WITH THE LEVEL RECORDER TYPE 2306
For full frequency analysis of sound and vibration signals, the output of the Sound Level
Meter can be connected to the 8 & K portable Level Recorder Type 2306. Synchroniza-
tion of the paper movement on the 2306 and the filter in use can be achieved by con-
necting the SYNCHRONIZATION socket of 1616 to the EXTERNAL POWER/REMOTE
CONTROL socket
of the 2306, using the control cable shown in Fig.3.6 . The cable is
not provided, but is available under 8 & K Stock No. AQ 0148.
1616
Synchronization
Fig.3. 6. Control Cable AQ 0148
2306
External Power/
Remote Control
760293
When the 2306 is switched on, the paper will advance until one (or both) of the 2306
FILTER SHIFT lamps and the 1 61 6 FILTER SHIFT LED are lit, and the paper will stop.
The FILTER SHIFT push
button is depressed manually and the paper starts moving again.
The push
button should be held down until the FILTER SHIFT lamp on the 2306 and the
1616 FILTER SHIFT LED are extinguished. The recording continues until the lamps light
again, and the whole sequence is repeated.
3.5.1. System Set-Up
12
A system
for semi-automatic frequency analysis is shown in Fig.3.7.
Before connecting the Sound Level Meter to the 2306, the attenuators of the Sound Lev-
el
Meter should be adjusted so that no overload will be experienced over the frequency

r--- -,
I
+i :
~~~~St::=: '~~.':_j~
,
.._,____._ _ __. I
2203 or 2209 1616
Sound Level Meter
1/3 Octave
Filter
2306 I
Level Recorder 1
I I
L_ _C£_nt.!:_o!_CaEI~ j
AQ o14g 750312 11
Fig .3. 7. System for semi-automatic frequency analysis
range of interest. Depending on the Sound Level Meter in use (2203 or 2209) and the
type of measurement (sound or vibration), the procedure described in § 3. 3.1, 3.3 .2,
3.4.1 or 3.4 .2 should be followed. The first items (Sound Level Meter in "Lin." mode)
ensure that the input stage of the Sound Level Meter, and consequently the Filter Set, is
not overloaded. When the Sound Level Meter is switched to "Ext. Filter", adjustment of
the OUTPUT A TIENUATOR should be made in the frequency band giving the highest out-
put signal. This position may also be used to adjust the Level Recorder controls so that
the pen deflects within the scale limits.
Connection between the Sound Level Meter output and the 2306 SIGNAL INPUT is
made via cable
AO 0116 (JP 0006 at one end and BNC plug JP 0035 at the other).
Note
that with 2209, choice can be made of AC or DC output.
3.5.2. Synchronization
1. Connect the system of Fig.3.7.
2. On the 2306, insert recording paper QP 0124 if a fibre pen is used, or QP 0224 if
a stylus is used.
3.
With the PEN DRIVE switched off, slide the pen to the left of the paper until it lies
on the 50 dB line.
4. With the PAPER DRIVE switched off, move the paper using the PAPER ADJUST-
MENT knob until the pen lies rv 1 mm before the third-octave frequency mark on
the paper corresponding to the desired starting frequency. (The third-octave mark-
ings are the small black rectangles on the 50 dB line.)
5. On the 1 61 6, select the filter corresponding to the frequency on the recording
paper.
6. Set the controls of the 2306 to:
DC LIN. POSITION }
SENSITIVITY
RECORDING
MODE
PAPER SPEED
WRITING SPEED/ LF LIMIT
PAPER DRIVE
POWER
PEN DRIVE
{
As determined in§ 3.5.1 of 2306 Instruction Man-
ual to give a suitable pen deflection
As required
As required
As required
Out
As required
In
The instruments are now synchronized for semi-automatic third-octave frequency analy-
sis.
13

The choice of PAPER SPEED and WRITING SPEED must take into account the ability of
the writing system to average fully. (See Instruction Manual for 2306.) Also, the PAPER
SPEED must be sufficiently low for the pen to be able to fall and rise between each third-
octave band, as the signal is completely cut off during the filter switching.
3.5.3. Frequency Analysis
1. Synchronize the system as described in section 3.5.2.
2. Depress the PEN DRIVE push button on the 2306. The paper starts and the level in
the first third-octave band is recorded.
3.
After 4 mm (or 5 mm for filter shifts after the first one), the paper stops and one (or
both)
of the 2306 FILTER SHIFT lamps and the 1 61 6 FILTER SHIFT LED light.
4. Depress the FILTER SHIFT push button on the 1616. The output signal is sup-
pressed,
the FILTER SWITCH is stepped by one third octave and the recording paper
starts again. The
FILTER SHIFT push button must be kept depressed as long as the
FILTER SHIFT lamp is lit or the paper will stop (and consequently, synchronization
wi II be lost).
5.
When the FILTER SHIFT lamps are extinguished, release the 1 61 6 FILTER SHIFT
push button. The output signal from the Sound Level Meter is again fed to the 2306
and recorded.
6.
When the paper stops and the FILTER SHIFT lamps light, repeat items 4 and 5 un-
til the frequency range of interest is analyzed.
A frequency analysis recorded
with such a system is shown in Fig.3.8.
• Bruel & Kjmr Bruel &
Kjmr Bruel & Kjmr
ODDDDOODO
OOOODOOOODODDODOOOOODDOOOOOOOOOOOOOOOODO
IBruei&Kjcer Range: 50 dB
Rectifier: RMS Lower Lim . Freq.: 4 Hz
Wr . Speed: 40 mm /sec.Paper Speed: 0,3 mm /sec.
COftenhe>ll" n
...
4nf?c
6C
!Measuring Obj .
4E
Gear Box
~
==
~·
JC
I ~=~~ , ~~-.1.75
15
!Sian .: D.J:H
0 :
~ jO
0
.
II Ze~~ Level: ~ dB
IO
)O ~0000 D
:Lin.
[OP 0124
Multiply Freq. Scale by 1
OU'"' "I
A B C Lin. 750291
Fig.3.8 . Example of frequency analysis recorded with the system of
Fig.3. 7
3.6. RMS MEASUREMENTS AND STATISTICAL ACCURACY
14
In any true RMS measurement system the accuracy of the data obtained is not only de-
pendent on
the system accuracy but also on the inaccuracies arising from the effect of
statistically random signals on the system's averaging process. To understand how these
.inaccuracies arise, it is necessary
to consider the RMS value of a signal which is defined~
lim _1 f T x2 (t) dt
T-ooT 0 3.1