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Aiwa's
Front
180°
Speaker
System
provides
excellent
sound
balance
for
true
stereo
reproduction
from any listening
ang"le.
In
stereo
sound
reproductions
systems
up
to
now, the listening
area where the optimal stereo
effect
is obtained
has been
extremely
narrow.
This is due to the following
reasons.
As
shown
in Figure
2,
a conventional
stereo
system
has speakers
on the front panel
of the
speaker system, pointing
forward. It is designed
for listening
in a location
directly
in front
of the front
speaker
panel.
In this case, as shown
in Figure
2, a listener
at point@,
located
on the center
line between
the right and left speakers,
hears the voice of
a
singer
coming
from
the
center
front.
Instrumental
sounds
are
distributed
evenly
between
both
speakers
for
an
optimal
stereo
effect.
At point
@), however,
located
off
the
center
c line between
the
speakers,
the distance
from
the
left
speaker
to
the
listener
is greater
than the distance
from the right speaker.
Sound
from the left speaker
appears
to be faint,
and
sound
from
the
right
speaker
appears
to
be
loud.
Sound
is perceived
as
coming
from
the
speaker
with
the greater
volume,
so that
the
singer's voice appears to shift toward the right
speaker.
The
normally
balanced
instrumental
sounds
also appear
to come primarily
from the
right
speaker.
Moreover,
since
the
directivity
of
speakers
increases
with
higher
frequencies,
high-
frequency
sounds
from the left speaker
become
even harder
to hear,
increasing
the impression
of imbalance.
For these reasons,
the listening
area which
provides
even sound balance
and the
optimal
stereo
effect
is limited
to the narrow
area
shown
in Figure
2-@.
.
To solve this problem,
Aiwa has developed
uni-
directional
speakers
for this new speaker system
featuring
cardioid
directivity
for frequencies
of 1 kHz
or less.
These
speakers
are pointed
inward
at angles
of 45°
(see Figure
1) ..Driven
by left and right
stereo
sound
signals,
these
speakers act to increase the width of the optimum
listening
area
(see Figure
3) . Because
of their
cardioid
directivity
and the 45° angle of their
main speaker
axis,
they provide
enhanced
sound
reproduction
at point@
in Figure
3. The left
speaker
is pointed
toward
the
listener,
and
the
right
speaker
is
pointed
away
from
the
listener, so that the directivity
of the speakers
compensates
for
the
differences
in perceived
volume
caused
by
the differences
in distance
to
the
listener.
Therefore,
the
sound
of
a
singer's
voice
is perceived
as coming
from
a
point
midway
between
the
speakers,
and
instrumental
sounds
are distributed
evenly.
EEm
Front 180° speaker system
Tweeter
Cardioid
speaker
speaker
I
Woofer
8
eaker)
DizEzl
Stereo effect with a conventional speaker
svstem
Main unit
Left
speaker
Right
speaker
@ Center listening point:
Balanced sound heard from left
and right speakers
@Off-center
listening point: Right speaker sounds louder
than left speaker
+: Sound pressure level
"'~'w$:r~~~'~ Stereo listening area
&@#&Q&#~
.......>> .
m
Stereoeffectwith
Aiwa Front 180" speaker
system
True stereo sound can beheard atpoint @aswell
aspoint
@.
Left
speaker
Main unit
+: Sound pressure level
:w%%wH&w: Stereo listening area of new speakers
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Right
speaker
EPIGLISH26