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

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

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

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

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.

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:_

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,

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,

~~:

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113

octave

analysis

:ac

~

10

'

and 2317

15

QP

o1s1

:~::

~::

,~:;:;;;:

~

2s

31

'5:

so

63

eo

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125

1eo

200

250

315

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500

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,

k~2~

u 2

z.s

3,

15

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.,

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

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.:

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:

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Level

:

80

0

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.:_

1ll

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~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

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

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

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

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

CONNECTOR:

"Recording On"

For

use when connected

to

a Level Recorder. An

ar-

row

on the

display

flashes

quickly

when

recording

a

frequency

band

(recording

paper

moving)

and when the Filter Set

controls

the

Record-

er. During the

filter

settling

time

(paper

not

moving) the

arrow

flashes

quickly

when RECORDING SPEED is set

to

"Fast",

and slowly when set

to

"Slow"

to

indicate

the longer settling

time

in the

"Slow"

position.

Note:

To

avoid

shortening the

battery

life, it is

recommended

not

to

switch

EXT. FILTER

"Off"

on the

Sourrct

~

t::e

·

'iTel

Meter

while the

"Recording

On"

arrow

is displayed.

It is

possible

to

externally

step

the

filter

to

a higher centre frequency

at

a

maximum

frequency

of

15 Hz, by applying a square wave on pin 3

(alternating open

circuit

and ground connection)

of

the RECORDER

CONTROL

socket

(see Fig.2.4). When the

"Lin."

setting is reached pin

5 is set

to

0

V.

Filter

Not Not

Signal

Filter

Output

-

11

V

OV

used

+

11

V

used

ground

Input

80088088

8080080

Not

used

ov

+5V

+Batt

.

-Batt

. Power -

5V

On/Off

830457

Fig. 2.3. 15

connector

for

Sound

Level

Meter

Type 2230

or

2233

RECORDER CONTROL:

8-pin

DIN

socket

for

synchronization

of

the Filter Set with the Level

Recorder

Type 2317, 2306

or

2309.

It is

possible

to

externally

step

the

filter

to

a higher centre frequency

at

a

maximum

frequency

of

15 Hz, by applying a square wave on pin 3

(alternating open

circuit

and ground connection)

of

the RECORDER

CONTROL

socket

(see Fig.2.4). When the

"Lin."

setting is reached pin

5 is set

to

0

V.

L:J

Filter

shift

pulses

from

Level

Recorder

0 V

to

stop

Level

Recorder

immediately

Not used Pulses

output

to

drive

Recorder

paper

Level Recorder

Ground

Fig. 2.4.

Recorder

Control

socket

830075

7

BATTERY DRAWER:

8

Fig. 2.5.

Side

view

of

the

Filter

Set

Battery

drawer

which

accepts

four

1

,5

V

alkaline

cells (IEC

type

LR6,

AA

size). These are

connected

in parallel

with

the

batteries

in the

Sound Level

Meter

(see

section

3.2). This

drawer

can be replaced

by

the

drawer

fitted

with

rechargeable cells

supplied

with

the

Mains

Pow-

er

Supply

and

Charger

ZG 0254

(optional

extra).

3. OPERATION

3.1. PRELIMINARY

The Type 1625 and the Sound Level

Meters

Type

2230

or

2233 have

matching

15-pin

push-fit

connectors

which

facilitate

direct

coupling

of

the instruments

to

form

one

com-

pact

unit. (See Fig.3.1

).

To

attach the Filter Set

to

the Sound Level Meter, press the

two

side-locks

and

engage

the

connectors.

Push the Filter and the Sound Level

Meter

to-

gether

gently

until the

two

side

locks

return

to

their

outer

position.

(See fig. 3.2.)

Fig.

3.

1.

Filter

Set

with

the

Sound

Level

Meter

Type 2230

To include the Filter Set in the

measurement

chain set the EXT. FILTER switch on the

Sound Level

Meter

to

"In".

The signal measured with the Sound Level Meter is then

filtered in an

113

octave

or

octave

band

of

centre

frequency

indicated

on the Filter Set

digital

display. The signal is also

frequency

weighted

as selected on the Sound Level

Meter, i.e.

"A",

"C",

"Lin.n"

or

"Lin."

(10Hz

to

50kHz). When no

frequency

weighting is

required,

it

is

recommended

that

the

"Lin."

rather

than the "Lin.

n"

mode

be employed.

The SPL

for

the selected 1;3

octave

or

octave

band is displayed on the Sound Level

Meter's

display.

9

Fig. 3.2.

Mounting

the

Filter

Set

on

the

Sound

Level

Meter

Type 2230

or

2233

3.2. POWER SUPPLY

3.2.1. Battery Check

The Filter

Set

is

powered

via

the

particular

Sound Level

Meter

connected.

The

batteries

contained

in the Filter

Set

are

not

used

to

power

the Filter

Set

directly,

but

to

increase

the

capacity

of

the Sound Level

Meter's

power

supply

and

to

retain the

preset

start

frequency

and the

current

centre

frequency

of

the Filter Set when

it

is

switched

off

or

unplugged

from

the Sound Level Meter. When using

with

Sound Level

Meter

Type

2230

or

2233 and

alkaline

batteries

are fitted, the

battery

life is

approximately

10

hours

.

To

check

the

battery

level

of

the

Filter

Set,

connect

the Filter Set

to

the

Sound

Level

Meter

and

remove

the

battery

drawer

from

the Sound Level Meter.

Switch

on the Sound

Level

Meter

and

note

whether

a

"BAT"

sign is

indicated

on

its

display. If the

"BAT"

sign

is

present

approximately

half an

hour

operation

time

is left (assuming no

batteries

in the

Sound Level Meter). If the

"BAT"

sign plus a

non-resettable

"t"

appear,

the

batteries

in

the Filter Set

must

be replaced,

or

recharged

if

Ni-Cd

cells

are

fitted.

Note: One set

of

batteries,

either

in

the

Sound Level

Meter

or

in

the

Filter

Set, is

sufficient

for

powering

both

instruments.

However,

the

battery

life

is

of

course

reduced.

For

long

term

storage,

it

is

recommended

that

the

batteries

are

removed

to

conserve

their

life

time

and as a general

safety

precaution.

3.2.2. Battery Replacement

10

Unlock

the

battery

drawer

and pull

it

out. Remove

the

deplenished

batteries

and

place

four

new

ones

with

polarities

as

shown

in the

battery

drawer.

Push the

drawer

back

into

place

until

the

lock

is

secured

. If the

"Recording

On"

arrow

flashes when EXT. FILTER

switch

is

set

to

"In",

press

RESET on the Filter

Set

and

wait

until the

arrow

stops

flashing. The

Filter

Set can then be

preset

to

the

desired

centre

frequency.

Fig. 3.3.

Battery

replacement

3.2.3. Mains Power Supply and Charger ZG0254 (option)

The

battery

drawer

of

the ZG 0254, containing 4

rechargeable

cells,

fits

into

the Filter

Set

Type

1624 and can be recharged either in

or

outside

the

instrument

via the

socket

on the side. The

Charger

delivers

enough current

for

simultaneously

powering

the Filter

Set and Sound Level

Meter

and recharging the cells

to

which

the

charger

is attached.

When only

recharging

the cells (drawer pulled out

or

instrument

switched

off), a

recharg-

ing

cycle

takes

approximately

5 hours. When recharging cells

while

powering

the

instru-

ment, the

recharging

time

is

of

course longer.

Note: It is

not

necessary

for

both

battery sets, in the Sound Level

Meter

and in the Filter

Set,

to

be rechargeable.

To

avoid

confusion, however,

only

those

with

rechargeable cells

have the

socket

receiving the charger mounted on the side. If

both

instruments have

rechargeable

battery

sets, it is necessary

to

use a

separate

power

supply

for

each set.

Fig. 3.4.

Mains

Supply

and

Charger

11

3.3. FREQUENCY

ANALYSIS

In the following sections emphasis is placed on the

practical

aspects

of

performing

113

octave

and

octave

analysis

with

the 1625. For a

comprehensive

theoretical

understand-

ing

of

frequency analysis, the

book

"Application

of

B& K

Equipment

to

Frequency Analy-

sis"

by

R.

B.

Randall should be consulted.

For

recordings

in AC mode, reference should be

made

to

the Level

Recorder

Instruction

Manual and

to

the

book

mentioned

above

for

a

proper

choice

of

Recorder

Paper

Speed

and

Writing

Speed settings.

3.3.1.

General

measurements

For

spot

measurements, the SPL in the

various

frequency

bands can

simply

be read on

the Sound Level

Meter

display. To

shift

the

frequency

band manually

proceed

as follows:

1.

Calibrate

Sound Level Meter (see

Instruction

Manual)

2.

On the Sound Level Meter set:

POWER:

REF.-OPERATE:

FSD:

RESET:

FREQ. WEIGHTING:

EXT. FILTER:

SOUND INCIDENCE:

DISPLAY:

TIME WEIGHTING:

DETECTOR:

3.

On the Filter Set:

STEP SIZE -BANDWIDTH:

RECORDING SPEED:

"On"

"Operate"

As

required

"All"

or

"Max./Min."

"Lin.",

except

if

a

frequency

weighting

is

to

be

ap-

plied

"In"

As

appropriate

"SPL"

(LT

for

Type 2233)

"Fast"

or

"Slow"

"RMS"

As

required

Irrelevant

4.

Set

the centre frequency

required

by

pressing

RESET

or

FILTER

"Up/Down".

If FIL-

TER

"Up/Down"

is kept depressed, the

centre

frequency

starts

stepping

continuous-

ly

after

a few seconds. The SPL,

corresponding

to

the selected

frequency

band is

displayed

on the Sound Level Meter.

Note: It is recommended to set EXT. FILTER

to

"Off"

before

the Sound Level

Meter

is

switched

"Off"

to

avoid

possible erasure

of

the "Preset Frequency".

3.3.2.

Third-Octave

Analysis

Recording

12

Fully

automatic

recording

of

octave-

or

1f3-octave

frequency

analysis can be

obtained

using Portable Level Recorders Types 2317, 2306

or

2309 (see Fig.3.5).

Since the Filter Set cannot

change

the

averaging

time

of

the Sound Level Meter, the

recording

speed is controlled

by

the Filter Set

to

obtain

an

accurate

recording

in the

minimum

time. To reduce the

fluctuations

in the

low

frequency

bands and

make

interpre-

tation

of

the

recorded

signal level easier, the TIME WEIGHTING on the Sound Level

Fig. 3.5.

Level

Recorder Type 2317

Meter

and the RECORDING SPEED on the Filter Set should be set

to

"Slow".

When

frequency

bands higher than 500

Hz

are the main interest,

it

is

recommended

to

set the

Sound Level

Meter

and the Filter Set

to

"Fast".

Recording with Type 2317

1.

Carry

out

preliminary

checks

on all 3 instruments

(battery

level, etc.) and

calibrate

the Sound Level Meter.

2.

Load the Level

Recorder

with recording

paper

QP 0124.

Connect

the Sound Level

Meter

to

Level

Recorder

using cable AO 0173, and

calibrate

the Level

Recorder

for

AC

Log

or

DC Lin (see Instruction Manual

for

Type 2230 and 2317).

3.

Fasten the Filter Set

to

the Sound Level Meter and

interconnect

the REMOTE

CON-

TROL

sockets

of

the Filter and Level Recorder as

shown

in Fig.3.5. With

earlier

Type 2306 Level Recorders use cable

AQ

0182 (see

section

3.3.4.).

Octave

Filter Set

1625

Two Channel

Level

Recorder 2309

'\

I

-.

-

•-

j

83004911

Fig. 3.6.

Set-ups

for

automatic

1ft

and

113

octave

analysis

and

record-

ing

with Type

2317

or

2309

13

14

4.

Set

the

Sound Level

Meter

as

described

in

section

3.3.1.

5.

Set

the

controls

on the

Filter

Set

as

follows:

STEP SIZE-BANDWIDTH:

RECORDING SPEED:

"1/3-

1f3"

"Slow"

or

"Fast";

corresponding

to

the

selected

TIME WEIGHTING on

the

Sound Level

Meter

(DC

Lin

recordings)

or

on

the

Level

Recorder

(AC

Log

recordings)

6.

Press

RESET

to

display

the

preset

frequency

which

is

always

the

starting

frequency.

To

change

the

preset

frequency

press

RESET (Preset Enable), and

while

keeping

it

pressed,

use the

"Up"

or

"Down"

push

buttons

to

step

the

filter

until the

desired

starting

frequency

is

indicated.

When

the

desired

starting

frequency

is

displayed

release RESET (Preset Enable).

7.

Set

the

Level

Recorder

as

follows

WRITING SPEED:

PAPER SPEED:

POWER:

PAPER DRIVE:

PEN LIFT:

"Normal"

"Ext."

On

Off

Proceed

with

recording

of

the

frequency

analysis, as

outlined

at

the end

of

this

section.

Recording with Type 2306 (or 2309):

1.

Carry

out

preliminary

checks

on all 3

instruments

(battery

level, etc.) and

calibrate

the

Sound Level Meter.

2.

Load

the Level

Recorder

with

recording

paper

QP 0124 (QP 2100

for

Type 2309). If

the

Sound Level

Meter

is

equipped

with

a DC

output,

connect

this

output

to

the

Level

Recorder

using

cable

AO 0173 and

calibrate

the

Level

Recorder

for

DC Lin

recording

(see 2230 and 2306

Instruction

Manuals).

If

the

Sound Level

Meter

used is

the

Type

2231, then

its

AC

Output

must

be used.

The

Level

Recorder

must

then

be

calibrated

for

AC

Log

recordings,

and

its

WRIT-

lNG SPEED

set

to

"1

00

mm/s"

(see

point

7).

3.

Fasten the Filter Set

to

the

Sound

Level

Meter

and

interconnect

the

REMOTE

CON-

TROL

sockets

of

the

Filter

and Level

Recorder

as

shown

in Fig.3.5.

With

earlier

Type

2306 Level

Recorders

use

cable

AQ 0182 (see

section

3.3.4.).

4.

Set

the Sound Level

Meter

as

described

in

section

3.3.1.

5.

Set

the

controls

on the

Filter

Set

as

follows:

STEP SIZE-BANDWIDTH:

RECORDING SPEED:

"1/3-

1f3"

"Slow"

or

"Fast"

corresponding

to

the

selected

TIME WEIGHTING

on

the

Sound

Level

Meter.

("Fast"

when using

Type

2231

).

6. Press RESET

to

display

the

preset

frequency

which

is

always

the

starting

frequency.

To

change

the

preset

frequency

press

RESET (Preset Enable), and

while

keeping

it

pressed,

use the

"Up"

or

"Down"

push

buttons

to

step

the

filter

until

the

desired

starting

frequency

is

indicated.

When

the

desired

starting

frequency

is

displayed

release RESET (Preset Enable).

7.

Set the Level

Recorder

as follows

RECORDING MODE:

WRITING SPEED:

PAPER SPEED:

POWER:

PAPER DRIVE:

PEN DRIVE:

"DC Lin"

"250

mm/s"

("1

00

mm/s"

when using Type 2231)

"Ext."

On

Off

On

Recordings

with

the Level Recorder Type 2309 are

similar

to

those

with

the

Type

2306.

Proceed

with

recording

of

the frequency analysis, as

outlined

below.

Recording

the

frequency

analysis:

Place the recording

paper

2,5

mm

before the

corresponding

centre

frequency

printed

on

the

recording

paper, and set PAPER DRIVE on.

Press RECORDING START/STOP to

start

the

automatic

recording. The

center

frequency

of

the

applied

111

octave

or

113 octave filter is displayed on the Filter Set. When

record-

ing is in

progress

(recording paper moving) the

"Recording

On"

arrow

on the

display

flashes quickly. During the

filter

settling time (paper

not

moving)

the

arrow

flashes

quick-

ly when RECORDING SPEED is set

to

"Fast", and slowly when set

to

"Slow"

to

indicate

the

longer

settling time.

Each 113

octave

is

recorded

over 5 mm.

At

the

start

of

each

113

octave

band

recording

the Sound Level

Meter

is disconnected

from

the filter and

the

pen

moves

downwards.

This allows

time

for

correct

averaging

to

take place and

permits

the pen

to

settle

to

the

correct

level

after

switching

from

the previous filter. When the

"Slow"

time

weighting

is

applied

to

the Sound Level

Meter's

detector, the RECORDING SPEED on the Filter Set

should be set

to

"Slow"

to

increase the time allowed

for

settling.

After

the last 113

octave

filter, a Lin (All-pass) filter is recorded. There

after

the

paper

moves

to

the

start

position

on the

for

a

new

analysis

to

be recorded.

To

repeat a frequency analysis press RECORDING

"Start".

To

immediately

interrupt

a frequency recording

momentarily

press RECORDING

"Start/

Stop".

To

resume recording, press the same button a

second

time.

After

a delay, the

recording is resumed and the last

part

of

the current

filter

recording

is

correct.

To

stop

the

recording

before

completion

of

the

frequency

analysis

press

RECORDING

"Stop"

and keep

it

pressed until the pen reaches the

bottom

line on the paper, and then

press RESET

before

releasing the RECORDING button. However, the

time

saved is

mini-

mal since the analysis

time

for

the high frequency bands is

short.

3.3.3.

Octave

Analysis

Recording

Automatic

Recording

of

Octave

analyses is

similar

to

that

used

for

third

octave

analysis

except

for

the

choice

of

step size and

positioning

of

the

paper.

For

octave

analysis

with

111

oct.

or

113 oct. step size, the STEP SIZE-BANDWIDTH

must

be

set

accordingly. The

pen

must

be

positioned

2,5

mm

before the

starting

centre

frequency

on the

paper

for

octave

frequency analysis with 113 oct. step, and 7,5

mm

before

for

octave

analysis

with

111

oct.

step

size.

15

Centre

1f3

Oct.

Centre

1f3

Oct.

Centre

1f3

Oct.

Centre

1f3

Oct.

Frequency

B.W.

at

Frequency

B.W.

at

Frequency

B.W.

at

Frequency

B.W.

at

3,7

dB

3,7

dB

3,7

dB

3,7

dB

Hz Hz

approx.

Hz Hz

approx.

Hz Hz

approx.

Hz

approx.

20 4,6 160 37 1,25 k 290 10 k 2300

25 5,8 200 46 1,6 k 370 12,5 k 2900

31,5 7,3 250 58

2k

460 16 k 3700

40 9,2 315 73 2,5 k 580 20 k 4600

50 11,6 400 92 3,15 k 730 Lin. -

63 14,5 500 116

4k

920

80 18,3 630 145

5k

1160

100 23

BOO

183 6,3 k 1450

125 29 1 k 230

Sk

1830

T00751GBO

Table

3.

1.

Third

octave

centre

frequencies.

Bold

characters

denote

preferred

series

for

full

octave

centre

frequencies

16

To

select

the series

of

centre frequencies

for

octave

analysis

with

octave

step

size,

first

switch

STEP SIZE

to

"1/3

Oct." and

preset

the

starting

frequency. Then

select

again a

"111

oct."

STEP SIZE. See Table 3.1.

Note:

When recording a frequency analysis

with

the Level Recorder Type 2317, the

"Fil-

ter

Shift"

LED will light each 5

mm

interval

of

paper

movement.

Remark:

The

band-edge

lines

of

the

recorded

analysis

may

be used,

to

determine

the BAND-

WIDTH and the STEP SIZE

of

the

recorded

analysis as well as the RECORDING SPEED

and TIME WEIGHTING used.

1.

With

a 50 dB range on the Level Recorder, the

"Fast"

time

weighting

gives

band-

edge

lines between the bands

approximately

32 dB long (See Fig.3.7

or

3.8), while

the

"Slow"

time

weighting gives lines 16 dB long (See Fig.3.9).

oooooooooooooooooooooooooooooooooooooooooooooooooo

Sr

Uel &

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r

RecOJd

l

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Mode

:DC

Li

n. 181 DC

Lo

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. 0

AC

Avet"eg

i

nt

__

Range

: _ (

dB

)

Paper

Spe

e

d

:

~

mm

/

s

Wr

.

Speed

:

~mm

ll

Rec .

No

.:_

dB

Date

:

__

10

Ti

me

:_ _

Si

gn

.:

_ _

Zero

level

:

~

C

Fig.

3.

7.

Third Octave analysis

on

Type 2317

d8

oooooooooooooooooooooooooooooooooooooooooooooooooo

BrUel & Kj

ar

Re

c

ord

i

ng

Mod

e: DC

Lin

R DC l og D AC

Log

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AC Av..-egi

ng

__

Ran

ge :

__§Q____

(dB)

Paper

Speed

:

~

mm

/s

Wr

Speed

·

~mmts

Rec.

No

.:_

dB

oate

:

__

10

Ti

me

:

__

~

9

,:

·=

L

ev

el

: 80 :

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~

~~

Ob

j

.:

_ 10

~

~.;:J~

-

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23m-

30

Qp

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~::

: :

~

:

,<:;'~

;:-

~

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ll

,

S~

~

50

63

80

1

00

125

11

50

200

2

50

JtS

<100

50

0

&30

800

1

k1

~

2~

1,6 2 2.5 3,

15

4 s 6.3 8 10

12

.5

16

20

lriiz~

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Fig. 3.8. Octave analysis with

third

octave

step

size

/2

BRUEL & KJAER 1625 User manual

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