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Aiwa’s Front 180° Speaker System provides
excellent sound balance for true stereo .
reproduction from any listening angle.
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
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.
DIiiEim
Front 180°$peaker system
Cardioid -
speaker
Surround-
speaker
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for uni-directional
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Stereo effect with a conventional speaker
1
system
Main unit
Left
speaker
Right
speaker
@ Center listening point:
Balanced sound heard from left
and right speakers
@Off-center listening point: Right speaker sounds louder
than leftspeaker
+: Sound pressure level
,;ilj$*@J: Stereo listening area
EEiEIz-”
Stereoeffectwith Aiwa Front180° speaker
system
True stereo sound can be heard at point@ as well as point
Main unit
Left
speaket
ENGLLSH26
