P%ti@@i3tl@riwh tm” s@c2AYts4/4tttw1- Figurel lFront180°speakersystem
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. I’cis 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
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.
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51 ,
R&ZG<‘,Cardioid speaker
!:,—Surround speaker
(Left speaker)
&
I Fiaure2 I Stereo effect with aconventional sr3eaker
11
system
Main unit
Right spl?aker
@ Center listening point: | Balanced | sound heard from left | |||
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| and | right | speakers |
listening | point: | Right | speaker sounds [ouder | ||
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| than | left | speaker |
+: Sound | pressure | level |
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:~;$jjj~~;y~j~:Stereo listening area |
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tEizEl Stereoeffectwith Aiwa Frcmt180° speaker system
True stereo sound can be heard at point @ as well as point
@.
Main unit
I
ENGLISH24
