Lexicon CP-1 PLUS V2.0 Owner's Manual page 50

CP-1 Digital Audio Environment Processor
Lexicon's implementation, called Panorama, was designed using measured
data on sound diffraction around the head to shape the frequency spectrum
of the canceling signal. This signal is then itself canceled by a second signal,
and so on, so that both the crosstalk and the signal that is canceling it are
eliminated.
Speaker Input Higher Order
Level Signal Correction
L
L
This works extremely well when the room is well damped and the listener's
head is correctly positioned. The first order devices described earlier
required the listener to sit on the center line between the loudspeakers, and
to arrange the angle between the speakers to correspond to the pro-
grammed delay. Although the CP-1 provides adjustments to compensate
for off-center listening and for varying speaker angles, maintaining a
consistent listening position is still important and becomes more so with
increasing frequency. With wide speaker angles, a movement of as little as
1 inch can make a perceptible difference. Fortunately, the effect is usually
fairly good everywhere within a zone about one foot wide.
To achieve the fullest Panorama effect, your main loudspeakers should
have good imaging. The smaller speakers that tend to be used with video
systems may have an inherent advantage here but the most important
requirement is that the two speakers have identical frequency response and
symmetrical dispersion. It is not necessary, or desirable, to turn your
listening room into an anechoic chamber but moving the speakers away
from the walls can be helpful, as can adding absorption (as provided by
carpets, curtains and/or sound-absorbent panels) to reduce the reflectivity
of the floor, walls and ceiling.
Speaker
Level First Order
R
R
L R
Higher Order
First order correction travels to left
ear, where it will be heard unless
canceled by an additional correction.
When these higher order corrections
are supplied, accurate cancellation is
possible.
Theory
and
Design
Page 45