Technics SH-8055 Service Manual page 4

ELEEEe
Mi PINK NOISE
ePink noise is used for measurement and correction of the
sound field frequency response because it is mostly within the
audible range, its energy distribution is uniform, and it has a Response of white noise Response of filter
wide frequency band.
dB
dB
Because pink noise has large instantaneous level fluctuations, _3dB/oct
the display may fluctuate. == ae
<Frequency response of pink noise> 3dB/oct
40
—_> f ———_—> I
$
Response of pink noise
30
20
- +
Level
10 20 50 100 200 500 1k 2k 5k 10k 20k 40k
Frequency (Hz)
HM HOW TO USE THE REAL-TIME SPECTRUM ANALYZER
@ With the sound volume of amplifier set at minimum, the frequency characteristics of sound sources such as human voice,
live music and noise can be measured (displayed on spectrum analyzer) through operations in numerical order as shown
below.
@ As the sound volume of amplifier is increased through operations as shown below, the sound volume of pink noise increases,
and then the sound field frequency characteristics can be measured (displayed on spectrum analyzer).
level.
Volume control: ''0"
® Balance control: ''center position"
~) Loudness switch: "'off"'
Q/elf the amplifier has a recording mode selector
and an input selector:
Input selector
elf the amplifier has a tape-monitor selector and
an input selector:
Tape-monitor selector
Excessively raising the amplifier 8 Tone controls:
volume or the band level controls of this "center position"
unit during measurement or correction
' could result in damage to the speakers
(tweeters); as the frequency increases,
the sound will approach the limits of the
audible range and be difficult to hear,
thus increasing the likelihood of a
mistaken assumption that there is no
output.
"on" (B_ m)
Recommended
microphone:
RP-3800E
(sold separately
"on" (Hm)
"0 dB" (m_. H)
*) Set the switch on the microphone to
(Change it over according to the
"on". sensitivity of microphone.)
(Position the microphone at the place and
@ Select the channel for sound field measurement by
height at which you usually listen to your
setting to "on" (H_ =).
audio equipment.)
Adjust the display so that it is easy to see (approximately
the 20-dB level).
(The display at this time shows the sound field frequency
response.)