BRUEL & KJAER 4409 User guide

Response Test Unit Type 4409
Test Records Types QR 2007-08-09
The test unit and recordings have been designed
to aid the accurate investigations of the frequency
response of sound reproducing equipment i.e.
record players,
tape & film recorders etc.
BHUEL & KJJEH
Ncerum, Denmark • ~ 80 05 00 . .;;;" BRUKJA, Copenhagen. Telex: 5316
BB 4409

Response Test Unit
Type 4409
Test Records
Types OR 2007-08-09
Reprint September 1965

Contents
1. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Purpose of the Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Description of the Test Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Recording Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Recorded Level Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Response Test Unit Type 4409 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Channel Selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Equalizing Filter ................... . .............................. 14
Synchro-Starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
General Description ................................................ 14
Functioning ....................................................... 16
2. Operation .............. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Practical Hints for Use of the Test-Records .......................... 17
Automatic Frequency Response Plotting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Automatic Gliding Frequency Cross-Talk Measurements .............. 19
General ........................................................... 19
Operating Procedure .............................................. 20
Synchronous Filtering Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Automatic Distortion Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Examples of Practical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Use of the Test Record QR 2008 .................................... 28
Spot Frequencies .................................................. 28
1 kHz Reference Tones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
100 Hz Tracking Test .............................................. 28
Tone Arm Resonance .............................................. 29
Test of Tape Recorders etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Synchro-Start of a Continuous Recording . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

1. DESCRIPTION
1. Description
Purpose of the Equipment.
The Response Test Unit Type 4409 is intended for use with the B &K auto-
matic frequency response plotting equipment when investigating the frequency
response of sound reproducing equipment.
Fig. 1.1 shows an example in which the 4409 and a test record are involved in
the testing of a stereophonic record player.
Head under test
Mic. Amplifier
Record Player
Level recorder
I
I
I
I
lAo. 0006
I
~~~~,L-----·-R~e~~t..:.~~~~J
962'165
Response Test Unit
Fig. 1.1. Measuring set-up for automatic plotting of the frequency response
of a stereophonic record player.
The 4409 fulfils three different functions:
(a) channel selection in the case of stereophonic equipment either manually,
when only one channel is investigated, or automatically at a recuring fre-
quency of 1.2 Hz for automatic cross-talk or comparison measurements.
(b) equalization, by different RC filters, of the recording characteristic of the
test record.
(c) synchronization of the paper-drive of the Level Recorder Type 2305 with
the reference recordings (record or tape) under reproduction.
It is thus possible to automatically plot the frequency response of the sound
reproducing equipment. A typical experimental result is shown in Fig. 1.2.
8

1. DESCRIPTION
Where the recorder is integrated with the reproducer, as in the case of tape
recorders, motion picture systems etc., reference recordings are taken from
the constant voltage output of a generator, but in the case of phonograph
testing, accurate reference disc recordings are needed.
The Gliding Frequency Recordings Type QR 2007 and 2009 are especially
designed
for the purpose of frequency response investigation. They provide
-""""-- ....
StlftophO!l!C
pick-up typ• • •
Ortafon SPli-G
Nnl
Fjlter I jn "
OR 2007 bondl
... ,..,__1___:_. "'
- 5·7· 1962
.,.,oo
'-""'-- -101
L.LA.tY ; __ _
,. lOdB
~~ .
......,,...~ . ... ;_ ,,tO
QP 1123 10
Fig. 1.2. Typical experimental result obtained by means of the set-up of Fig.
1.1.
(Test of a high quality stereophonic head presenting a certain unbalance).
The total duration of one plot is 35 sec. between the instant when the pick-up
is put down on the record QR 2007 and the instant when the set-up is ready
to start a new plot.
continuous frequency sweeps from 20 Hz to 20 kHz, with lateral modulation
on the QR 2007 and left, right, lateral, ve rtical modulations on the QR 2009'.
The Pickup Test Record Type QR 2008 is, on the other hand, designed for
measurements at fixed frequencies and for tone arm resonance investigations.
It is intended for pick-up design work, and also for general purpose checks in
combination with the gliding frequency records when curve plotting equipment
is not available.
Description of the Test Records.
General.
The B & K reference recordings are delivered in boxes containing five identical
vinylite records and one instruction manual (Fig. 1.3).
Both sides of each record being identical, a total of ten sides are available,
a
large enough quantity to guarantee a great number of playings without
4

1. DESCRIPTION
alteration of the characteristics. This number, however, is greatly dependent
on the care exercised in the use of the records. By conserving one side as a
reference,
it is possible to check on the service life of each record in use.
Fig. 1.3. Gliding Frequency Recordings Type QR 2007.
The cutting process and the dimension are in accordance with the Recom-
mendation of the International Electrotechnical Commission (IEC 98/98-1)
recognized
by most countries.
The detailed specifications are given at the end of this manual.
The reproduction of the label of the QR 2007 (Fig. 1.4) and the photograph
of a section of the record , illuminated by a grazing light beam (Fig. 1.5),
show the exact composition of the recordings.
The QR 2008 and QR 2009 are described in the same way by figures 1.6
through 1.9.
The original sinusoidal signal used for recording the disc tracks was obtained
from a B & K Beat Frequency Oscillator with especially low distortion. For the
recording of the gliding frequency bands the frequency of the signal was varied
according to a function of time which was purely logarithmic within .± 2.2 %
± 1.3 Hz.
This tolerance is equal to the tolerance on the determination of the recorded
frequency when using the Gliding Frequency Records at the exact specified
rotation speed ( 45 rpm) and assuming a logarithmic sweep.
5

1. DESCRIPTION
Briiel & Kjaer
Copenhagen Denmark
Monophonic
Gliding Frequency Record
20-20000 c/s
Type OR 2007
0
45 r.p.m. D
Frequency Sweeps: Logarithmic 20 c/s to 20 kc/s in 15 seconds
Start Marking (20 c/s point): Cease of the 1 kc/s signal preceeding each band
Recording Characteristic:
IEC Standard No. 3 without treble emphasis
(constant velocity above 1 kc/s) .
Recorded Velocity
at 1 kc/s: 3. 16 cm/s r.m .s.
Bands 1 to
10: lateral cut
fig. 1.4. Label of the QR 2007.
2
4
10
QR 2007
Bands 1 to 10 : A B
20 cfs 20 kc fs
8/9 octave per rev.
Fig. 1.5. Section of the QR 2007 showing the succession' of gliding frequency
bands preceded by a 1 kHz start and reference signal.
6

Bruel & Kjaer
Copenhagen Denmark
Pick-up Test Record
33
1
/a r.p.m. 6
Section 1
Vel~~;~: r:r:~~o~si~~~.~
0
c ~-~~.~ i~
2
15; ~~dku~~tion.
Band 1: 45 ° left modulation (A). Band 2 :45 ° right modulation (B).
Section 2 0 Section 3
Reference Tones, 1 kc/s, 4 x
60 sec . · Lateral Tracking Test,
Velocity level: 2. 24 em/sec. rms (45 °) 100 c/s (A+B), 5 x 15 sec .
(3.16 cm/s lateral or vertical) Band 1:
0.001 em peak amplitude
Band 1: 45 ° left (A~ Band 2: 0. 002 • • »
==~~ ~~ t!;e~~~h(~~)B) ==~~ =~ g : ~ : :
Band 4: vertical (A-B) Band 5: 0. 005 » »
Section 4
Vertical Tracking Test, as section 3 but with vertical (A-B) modulation.
Section 5
Logarithmic Frequency
Sweeps 10 c/s - 100 c/s in 16'/• sec .
Start Marking (10 c/s point): cessation of the 1 kc/s signal
Recorded levef:r~~~~i~~t ~':::;li~~d~ · 0.00113 em peak .
==~~ ~~ :~ ~ ~~~~~~~) ==~~:~~~~~~~~~(~A~~)
Section 6
as section 1, but with small groove speed
'?ec0,., . "'ef\\ 163696
ded on ORTOFON Eo.\l'll
Fig. 1.6. Label of the QR 2008.
Spot frequencies }A
20-16-12.5-10 kc/s 8
(0.6 em/sec rms)
1kc/s reference
}~
tone (3 . 16 cm/secl
A-8
Tracking test I
(compliance) . A+8
100 cts bands of
increasing ampl.
A-,8
0. 001 to 0.005 em
10-100 C/S sweeps}A
constantamplitud 8
(0 . 00113 em peak) A+8
for tone arm A-8
resonance
as first section }~
QR 2008
2
3
5
6
(33113 rpm)
+t.'3462
1. DESCRIPTION
Fig. 1.7. Section of the QR 2008 showing the succession of bands.
7

1. DESCRIPTION
Brtiel & Kjcer
Copenhagen Denmark
Stereophonic
Gliding Frequency Recor~
20-20000 c/s
Type OR 2009
0
45 r.p.m. ,6_
Frequency Swaaps: Logarithmic 20 c/s to 20 kc/s in 50 seconds
Start Marking
(20 c/s point) : Cease of the 1 kc/s signal preceeding each band
Recording Characteristic: IEC Standard No.3 without treble emphasis
(constant velocity above 1 kc/s) . ·
Recorded Velocity
at 1 kc/s: 2.24 cm/s r.m.s. in 45 ° modulation
(3.16 cm/s
in lateral and vertical modulations)
Bands 1 and 5:
45 ° left modulation (A)
Bands 2 and 8: 45 ° right modulation (B)
Bands 3 and 7: lateral modulation (A+B)
Bands 4 and
8: vertical modulation (A-B)
Fig. 1.8. Label of the QR 2009.
B
~
AtB
~
A
8
A+B
A- B
Pig. 1.9. Section of the QR 2009 showing the succession of gliding frequency
bands preceded by a 1 kHz start and reference signal.
8