BRUEL & KJAER 1625 User manual

InstructionManual
1 /3 - 1/1 Octave Filter Set Type 1625
Briiel a KJar
Type 1625
Fast~ Slow
Recording Sptled
Filter Step
~~·
·~
•
Step Size
1/ 3!1ji; / 1 Oct .
1/ 3 111 111 Oct.
Bandwidth
1/ 3 ..... 1/1 Octave Filter Set
A portable Band Pass Filter Set primarily in-
tended
for use with Sound Level Meter Type
2230,
2231 or 2233. Permits third-octave
frequency analysis, and octave frequency
analysis with a step of octave or third-oc-
tave. Fully automatic recording of the analy-
sis is possible with a Level Recorder Type
2317, 2306
or Type 2309. The scanning of
the filter and the Level Recorder are fully
controlled by the Filter Set
to obtain an op-
ti'Tlal recording. Two scanning speeds are
available for analysis of levels measured
with
"Slow" or "Fast" time weighting.
The selectable centre frequency range is
from
20Hz to 20kHz and a linear position
gives a frequency band from
3Hz to 75kHz.
The analysed signal may also be weighted
by selecting
"A" or "C" frequency weight-
ings on the Sound Level Meter.
+ BrUel &Kjrer

1Ja- 111 Octave Filter Set Type 1625
From serial no. 1032782
Revision
May 1985

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS (PRODUCT DATA)............................................................................ 1
2. CONTROLS..................................................................................................................................................................5
3. OPERATION.................................................................................................................................................................9
3.1. PRELIMINARY ........................................................................................................................9
3.2. POWER SUPPLY..................................................................................................................10
Battery check........................................................................................................................10
Battery replacement ............................................................................................................10
Mains Power Supply and Charger ZG 0254..................................................................... 11
3.3. FREQUENCY ANALYSIS.....................................................................................................12
General Measurements .......................................................................................................12
Third-Octave Analysis Recording ......................................................................................12
Octave Analysis Recording ................................................................................................15
Frequency Analysis controlled by Level Recorder..........................................................17
4. APPENDIX ................................................................................................................................................................. 19
5. SERVICE AND REPAIR ........................................................................................................................................... 21

USES:
• Filter Sets
for Sound Level Meters
• Semi-automatic octave noise analysis (Type 1624)
• Automatic 113 octave and octave (with 111 or 113
oct. step) noise analysis (Type 1625)
• Attenuation of background noise
• Distortion measurements
FEATURES 1624:
• 10 octave filters in accordance with IEC
R 225-1966, DIN 45651 and ANSI S1.11-1966
Class II requirements; and unweighted linear
response
• Centre frequencies from 31 ,5Hz to 16kHz,
frequency range 22Hz to
22kHz (octave), 5Hz to
75kHz (Lin)
• 0dB nominal filter attenuation
Bruei&KJa
Type 1624
Ready for
neKtfilter
types 1624 and 1625
Octave Filter Set and
Third Octave/Octave Filter Set
• Loudness evaluation in accordance with ISO R
532 (Stevens and Zwicker)
• Noise checking to octave and third-octave limiting
curves
• Building acoustic measurements
• Sound power measurements on machines
FEATURES 1625:
• 31 third-octave and 31 overlapping octave filters
in accordance with IEC R 225-1966, DIN 45651,
DIN 45652, and ANSI S1.11-1966 Class II & Ill
requirements; and unweighted linear response
• Centre frequencies from 20Hz to 20kHz,
frequency range
18Hz to 22kHz (1/3 oct.)
and
14Hz to 28kHz (oct.), 3Hz to 75kHz (Lin)
• 0dB nominal filter attenuation
Centre Frequency
Hz
lin o
16 k.
8 k •
....
Recording
On
...
Reset
!l'r,;set Enable)
Centre Fr.,quency
Briiel& Kjaer
Type 1625
Hz
Filter Step
(Preset,
Octave Filter Set Type 1624 and
Third Octave/Octave Filter Set Type
1625 are primarily designed for use with
Sound Level Meters Types 2230, 2231
and 2233 for in situ octave and lja octave
acoustic analyses.
The Type 1624 en-
ables octave analysis
to be carried out,
while Type 1625 offers lja octave analy-
sis
and octave analysis in octave or lfa
octave steps. Both filters are compatible
with
either of the Sound Level Meters,
forming a complete, compact
and porta-
ble, lightweight unit. Semi or fully auto-
matic analysis recording is possible with
a portable Level Recorder
Type 2317 or
2309.
• 2 k •
+ ;;·
Start
•
Octave Filter Set
BP 0106-14
250.
U6o
63 •
31.6 .
Stop
Recording
Step Size
1 / 3 1/ 3 1/ 1 Oct .
Fast
Slow
1 / 3 1 / 1 1/ 1 Oct .
Bandwidth
Recording Speed
1/ 3 - 1/ 1 Octave Filter Set

Fig. 1. Sound Level Meter Type 2230 with
1/3- 1/1 Octave Filter Set Type 1625
The Octave Filter Set Type 1624
and the Third Octave/Octave Filter
Set Type 1625 are both active filters,
which are small
in size and light
weight. Both are easily fitted to the
bottom of the Sound Level Meter
Type 2230, 2231 or 2233, ensuring
both mechanical and electrical con-
nections
with proper matching of in-
put and output impedances.
Adding a Filter Set to a Sound Lev-
el
Meter greatly extends the uses of
the instrument, enabling detailed fre-
quency analysis
to be carried out.
The overall frequency range of both
filters sets covers the entire audio-fre-
quency range
with the centre frequen-
cies arranged according to the pre-
ferred frequencies
of ISO R 266, DIN
45401 and ANSI S 1.6-1960. The fil-
ters may be switched in successively
manually (Type 1624 or 1625), or
automatically (Type 1625). The level
in each frequency band is displayed on
the Sound Level Meter and may be
noted in a measurement report or
plotted on graph paper. For greater
convenience the analysis can be re-
corded
in situ, either semi-automati-
cally (Type 1624) or automatically
(Type 1625) using one of the portable
B &K Level Recorders Type 2317 (one
channel)
or Type 2309 (two channels).
The signal fed to the Filter Set is
also weighted as
selected on the Sound
Level Meter ("A", "C", "Lin. 20Hz to
20kHz" or "All Pass 10Hz to 50kHz").
Octave Filter Set Type 1624
The Type 1624 permits octave fre-
quency analysis
when used with a
2
DDDDOOODOOOOOOODOOOOOODOODODDDDOOOOOODDOOOOODOODOD
BrUel & Kj cer Potentiometer Range ~ _ _ d9 Rectifier: __ lower Lim. Freq .: __ Hz Wr . Speed: __ mm/sec Paper Speed :_ mm/sec.
52 ;1<>-75
Measuring Obj .:
---4020
---315
Rec. No .: _
Date: __
Sign .: __ 0 0
10 dB
10 20 Hz 50
OP 1124 Mulliply Frequency Seale by : 100 200 2
kHz 10 20
( 1612/2112)
8 60
6 5
4 po
2 5
0 0
40 0 A B C Lon .
A B C Lin .8J0067
Fig. 3. Frequency characteristics of the 10 octave filters in Type 1624
Sound Level Meter. The analysis can For semi-automatic recordings, the
be recorded semi-automatically with Filter Set is connected to the Level
the Level Recorder Type 2317 or 2309. Recorder by the control cable AQ
The Type 1624 contains 10 active
octave filters
with centre frequencies
from 31,5
Hz to 16kHz. Each octave
filter satisfies
the requirements of IEC
Recommendation R 225-1966, DIN
45 651 and ANSI Sl.ll-1966 ClassII,
see Fig.2.
The total frequency range is
from
22 Hz to 22 kHz as can be seen in
Fig.3. A linear position is also avail-
able covering
the frequency range
from
5Hz to 75kHz (-ldB).
m-2
"0 -1
5 0
·.p 1
~ 2
~ 3
~ 4
5
10
11
12
13
14
15
16
17
16
19
0034. The ground connection is en-
sured by cable AO 0173 used to con-
nect the Sound Level Meter to the
Level Recorder. See Fig.4. The SPL
for the selected frequency band is ob-
tained from the Sound Level Meter
Output, and the start/stop of paper
movement is controlled by the Filter
Set. The recording is made on gradu-
ated paper with a scale of 15 mm/oc-
tave, such as QP 0124 for Type 2317.
Level Recorder
2317
w ~
v •
n ~
0.5 0.6 0.7 0.6 0.9 1.0 1.2 u 1.6 1.6 2.0 2.5
Frequency relative to centre frequency f/fm
170125/2
Fig. 2. Top of an octave filter characteris-
tic from
the Filter Set Type 1624
Two Channel Level
Recorder 2309 850216
Fig. 4. Set-ups for semi-automatic octave
analysis
and recording with Type
2317 or 2309
oooooooooooooooooooooooooooooooooooooooooooooooooo
BrUel &Kiar Re co rding Mode·DC Lin Cl!l DC Log CJ ACLog 0 AC A..,-aint __ Aange: 2.Q__(d8• Paper ~peed : _ 3 _ mm/s Wr Speed· 250 mm /s
l
lllt~tlii!Jitl.l!lllliiiii!IIIJIII!tllrl1111"1lll~_l l_l_J
10
Aec. No .: __ dB B
Date! __
10
Tim• : __
Si gn .: __
Zero Levei,Jl.Q_ 0
M:~~~eob; . : _
1c
~
analysis 20
~
and
231
~~ ~ ~. Oct..--f-- 31 .5 Hz 63 125 250 500 1kHz 2 16 Lin .
QP 0151 St•rt Llf'e t/3 Octr~•- 20 25 40 so so 100 110 200 ~s 400 no 800 us t,& 2.s 3,ts 10 t2,5 20 !2s 3,
15
Fig. 5. Octave analysis of machine noise using the set-up in Fig.4
1613/161
83031912

When recording each octave, the fil-
ter output is disconnected from the
Sound Level Meter during the first
millimetre which corresponds
to the
settling time. Once the recording of
one octave is completed,
the paper
stops and the indicator READY FOR
NEXT FILTER lights up. At the end
of the analysis the SPL with the linear
weighting (or "A" or "C" if applied on
the SLM) is recorded.
1/3-lfl Oct. Filter Set Type 1625
The Type 1625 permits 1/ 3 octave
and octave frequency analysis. Octave
frequency analysis
can be made with
octave or 1/s octave step size. An un-
weighted frequency response (Lin)
from 3
Hz to 75 kHz is also available.
The Type 1625 contains 31 active 1/ 3
octave filters and 31 overlapping 1/1
octave filters at 1/ s octave intervals
covering 11 octaves. Centre frequen-
cies are from
20Hz to 20kHz. Each
filter fulfils the requirements of IEC
recommendation 225-1966, DIN 45652
and ANSI Sl.11-1966 Class III for 1/ s
octave filters; and DIN 45 651 and
ANSI Sl.11-1966 Class II for 1/1 octave
filters, see Fig.6.
The total frequency
range is from
18Hz to 22kHz (1/3 oct.)
and from 14Hz to 28kHz (1/1 oct.).
The level in each frequency band
can be read on the Sound Level Me-
ter's digital display, the centre fre-
quency of the filter being displayed on
the Filter Set. The filter centre fre-
quency being selected manually by
push button.
When the Filter is connected to a
Level
Recorder Type 2317 or 2309 the
recording of the analysis and the filter
stepping is carried out automatically.
The Level Recorder is connected to
the Sound Level Meter using cable AO
0173,
and to the Filter Set using con-
trol cable AQ 0034. See Fig.7.
The filter scanning is electronically
programmed and controlled to obtain
an RMS read out error less than 0,5
dB over the whole analysis range. The
settling time and the paper drive
speed are controlled by the Filter Set
to ensure a precise recording in a
minimum time.
The filter scanning is electronically
controlled
and programmed to opti-
mise
the recording. The Filter Set in-
creases
the Level Recorder paper
speed as the analysis band centre fre-
quency is increased. Thus, an accurate
recording is obtained in a minimum of
time.
co
-2
"0
Max. Ripple
c:
0
0 (peak-to-valley)
· ~
2 0,5
dB
:::1
c:
IEC
QJ
4
t:
<(
(DIN 45 652)
6
8
10
12
14
16
18
20
22
0.4 0,6 0,8 1 1,4 1,8 2,5
0,5 0,7 0,9 1,2 1,6 2,0
Frequency relative to centre frequency f/fm
170124/1
Fig. 6. Top of a 1 /3 octave filter characteris-
tic from
the Filter Set Type 1625
Two Channel Level
Recorder 2309 850217
Fig. 7. Automatic I/3 octave analysis and
recording with Type 2317 or 2309
oooaoooooooooooooooooooooooooooooooooooooooooo . oaoo
Bru.t&Kjar
20
Re<ordlngModo:OCL in. 1:81 DCLog .CJ ACLog .CJ ACAvor'\II .. __ Ronge :_ (dBI Pa .. r$pead , ~mm/o Wr . Spead : ~m~
Aee . No .: __ dE
Ooto: __
1c
Ti m• :-- ,
~~: ·' Lovo o, ..§Q. C
~~ct:~eObi- '- tC
113 octave
analysis
:ac
~
10 '
and 2317
15
QP o1s1 :~:: ~:: ,~:;:;;;: ~ 2s
31
'5: so
63
eo H)()
125
1eo 200
250
315 .oo
500
s)O eoo , k~2~ u 2 z.s 3, 15 , .,
8
10 12 .5
14
20 @1 ~:]
1
" · 3.~·· ~JE:~ti1~311!!Jtl
83032112
Fig. 8. Third-octave analysis of machine noise using the se t-up in Fig.7
oooaoooooooooooaooooooooooooooooooaooooooooooaoaoo
BrOot & Kjar Re<ordlng Modo:, OC Lin. R DC Log. CJ AC L og . CJ AC A-aolno -- Ronge, 2Q__(dBI Po .. r s .... ,~ mm /s Wr. Spead : ~m/o
w 10
R.e . No .: __ dB
O•te : __ ,O
Time : __ •
~~: : Level : 80 0
~~~h'l;;'e Obj .:_ 1ll
~
~oct. stef~
10
1l:2~i~:~;-
Start j'! Oc:taw___;~ 31 ,5 Hz 63 125 250 500 1kH z 2
QP 0151 St•rt L IM t/3 Oct.aw- 20 25 40 50 80 100 180 200 3t5 <400 630 1!100 1, 2$ U 2.5 3, 15
Fig. 9. Octave analysis with
1/3 oct.
step size of machine noise using the set-up in Fig.7
The starting frequency is selectable
to eliminate low frequency compo-
nents and the analysis can be inter -
rupted and restarted during recording
with the "Start/Stop" push button. An
analysis can also be stopped before
completion
and the paper automati-
cally moved to the next start position,
ready for a new run.
Recording of octave analysis with
1/ s
octave or 1/1 octave step size is also
automatic. For octave analysis with
octave step size, a choice between
three series of centre frequencies is
offered (lowest frequencies 20,
25 or
31,5 Hz).
Two analysis recording speeds
("Fast" or "Slow") are available to al-
low for stabilization
of the Sound Lev-
el
Meter detector depending on
whether a "Fast" or "Slow" time
weighting is selected on the Sound
Level Meter.
Power supply
The active filters contained in the
Filter Sets are powered from the
Sound Level Meter through the 15 pin
connector, provided the EXT. FIL-
TER switch on the Sound Level Meter
is set to "In". The battery pack in the
Filter Set contains 4 cells IEC LR 6
(B&K No. QB 0013) and is always
connected in parallel with the battery
pack in the Sound Level Meter. The
battery life (alkaline cells) of the
Sound Level Meter/Filter Set is ap-
proximately 12
hours with the Type
1624 and approximately 8 hours with
the Type 1625. The Mains Power Sup-
ply and Charger ZG 0254, including a
drawer
with rechargeable cells can be
used
to power the Filter Set.
3

Specifications 1624 and 1625
Filter Set Type 1624 Octave 1625 Third-Octave and Octave
·<·
Frequency Range
Selective
22Hz to 22kHz
18Hz to 22kHz (1 /3 oct) , 14Hz to 28kHz (1 11 oct.)
Linear Typical
5Hz to 75kHz (- 1 dB) Typical
3Hz to 75kHz (-1 dB)
''
Band-Pass Filters 10
active 6-pole Butterworth octave filters 31 active 6-pole Butterworth third-octave filters and
31 overlapping 111 oct. filters at 11 3 oct. intervals
covering 11 octaves
In accordance with standard IEC R 225-1966, DIN 45
651 and IEC R 225-1966, DIN 45 652, DIN 45
651 and
ANSI S 1,11-1966, Class II ANSI SU1-1966 , Class II & Ill
Centre Frequencies
31 ,5 Hz to 16kHz 20 Hz to 20 kHz
Attenuation at Centre Frequency 0 dB ± 0,5
dB 0 dB ± 0,5 dB
Peak-to-v.alley Ripple < 0,5 dB < 0,5
dB
Attenuation outside Pass Band See Fig.2 & 3, > 60 dB at 8 f0 and 1/s f0 See Fig.6, >
75 dB at 5 f0 and 1fs f0 (1/3 oct.)
> 60 dB at 8 f0 and 1fs f0 (1 11 oct.)
Filter Shift
Sl i der switch Manual or Automatic with Level Recorder . 11 3 oct. or
Green lamp indi cates time for filter switch i ng
111 Oct. steps for 111 oct. analysis
when used
with Level Recorder
Remote Control Semi
automatic of Level Recorders Types 2317 and Automatic to/from Level Recorders Types
2309 via cable AQ 0034 2317 and 2309
via cable AQ 0034
Input Impedance 10 kQ in series
with 5 JLF 10 kQ In series with 15 JLF
Input Tt~rminat i ng Impedance
.::;;; 100 n .::;;; 100 n
Input Voltage Max. 2 V sinus (2,8 V peak)
Max . 2 V sinus (2,8 V peak)
Output Impedance < 5 Q in series with 15 JLF
< 5 n·in series with 2,2 JLF
Output Terminating Impedance
;?::: 10k Q //1nF
;:::: 10kQ//1 nF
Inherent Noise f0 Hz max. JL V f0 Hz (oct.
or 1 f3 oct.)
max.JLV
31 ,5 Hz 200 (typ. 140)
20Hz-40kHz 250 (typ.170)
63Hz - 16kHz
150 (typ. 70) 50Hz-10kHz 150 (typ. 80)
Lin 250 (typ. 120) 12,5 kHz-20 kHz 200 (typ.11 0)
Lin 250
(typ .120)
Magnetic Sensitivity (50 Hz)
Approximately 1 mV output for 100 A/m field strength
Operating Temperature -10
to + so oc (+ 14 to +122° F)
Storage Temperature -20 to +50 °C (-4 to +122° F)
Batter ies Removed
Influence of Temperature on Attenuation < 0,5 dB (-10 to +50B°C)
Influence of Humidity on Attenuation ·< 0,5
dB for 0 to 90% relati ve humidity at .::;;; 40°C without condensation
Batteries 4 x 1,5 V IEC Type LR6 (QB 0013). Batteries used as extra supply for SLM
Dimensions
Length 105 mm (4,1 in) .::. Width 85 mm (3,3 in) -Height 47 mm (1 ,8 in)
Weight \ 450 g (1 lb) including batteries
Accessories Included 4 Alkaline
batteries
QB 0013
1 Plug JP 0802
Accessories Available 1,5m
control cable AQ 0034
1
,5m contro l cable
AQ 0182
Ma ins Power Supply and
Charger ZG 0254
T 005 17GB1

RESET (Preset Enable):
RECORDING
Start/Stop:
FILTER STEP (PRESET):
2. CONTROLS
Re<:mding
On ...
R eset
(P reMt Enable}
Recording
Bruel & Kjaer
Type 1625
Fast Slow
Recording Speed
Filter Ste p
(Preset}
, Step Si:re
1 / 3 113 1 / 1 Oct ,
1/ 3 1/ 1 1/ 1 OcL
Bandwidth
1/3 - 1/ 1 Octave filter Set
Fig. 2. 1. Front view of the Filter Set Type 1625
Resets the centre frequency of the filter to a preset centre frequency.
When
connected to a Level Recorder, it actuates the paper drive to
move the paper forward to the preset start frequency on the next
chart. It also allows setting of the preset centre frequency (see FILTER
STEP (preset)).
Start/stop push button for the automatic filter scanning and the paper
drive on the Level Recorder. The button is operative only if a Level
Recorder is connected and switched on. The filter dwell time at each
frequency band is programmed to allow optimal recording over the
complete frequency range of the analysis.
The analysis can be stopped at any time by momentarily pressing this
button, and
restarted by pressing it a second time. During this stop,
the
"Recording On" arrow (see below) stops flashing.
Two push buttons for manually stepping the centre frequency of the
111 octave or 113 octave filter.
"Up" Shifts the centre frequency one step higher when momentarily
pressed. When pressed and held in, the filter steps continuously after
a short delay.
"Down" Shifts the centre frequency one step lower when momentarily
pressed. When pressed and held in, the filter steps continuously after
a short delay.
5

RECORDING SPEED:
Fast
Slow
The centre frequencies are from 20 Hz to 20 kHz for both 1f3-octave
and
octave bands. See Table 3.1 for the 1f3 octave and preferred oc-
taves centre frequencies.
When RESET (PRESET ENABLE) is pressed, the
preset centre frequen-
cy of the Filter Set can be changed using the FILTER STEP (PRESET)
"Up" or "Down" push buttons.
Note:
-
Provided that the batteries produce sufficient voltage for stand-by,
both the
preset frequency and the centre frequency to which the Filter
was set are retained in the memory when the Filter Set is switched off
or detached from the Sound Level Meter. To be certain that these two
frequencies will be retained, it is recommended to switch EXT. FILTER
"Out" before the Sound Level Meter is switched off.
-When the Filter Set is
not powered (EXT. FILTER "Out" or Sound
Level Meter "Off") all its push buttons are inoperative.
-The Filter is
electrically disconnected from the Sound Level Meter
while the push buttons are depressed .
Two position slide switch for adapting the filter sweep speed to the
time weighting used on the Sound Level Meter. Set to "Fast" when
measuring with the
"Fast" time weighting on the Sound Level Meter;
and
to "Slow" when measuring with the "Slow" time weighting.
1fs Oct. - 1fs Oct.
(20 Hz -20 Hz)
3 min.
50s
7 min. 40 s
1fs Oct. - 1f1 Oct.
(20 Hz -20 Hz)
2 min. 15 s
6 min. 10 s
1f1 Oct. - 1f1 Oct.
(31 ,5 Hz - 31 ,5 Hz)
1 min. 20 s
2 min.
50s
T00504GBO
Table 2.1. Typical time from the beginning of one analysis to the beginning of the next one
STEP SIZE -BANDWIDTH:
LIQUID CRYSTAL DISPLAY:
6
Three position slide switch for selecting 1 /3 octave bandwidth (1/3 oc-
tave step), 111 octave bandwidth (1/3 octave step) or 1f1 octave band-
width (111 octave step) frequency analysis.
"Centre Frequency Hz" Digital display indicating the centre fr~quency
of the applied filter .
Fig. 2.2. Centre Frequency display