3Com CP-1 Two-Way Radio User Manual

Page 11
CP-1 Digital Audio Environment Processor
PANORAMA works by canceling the sound going from each speaker to the
opposite ear. The effectiveness of the program is highly dependent on the
geometry of your front loudspeakers, the room and your listening position.
The correct timing of the canceling signal varies with the angle between
your main speakers. The SPEAKER ANGLE parameter, displayed in de-
grees, adjusts for wide or narrow speaker spacing. For the two canceling
signals to arrive at both ears at the same time you must be centered precisely
between the speakers. The Listener Position parameter (LISTENER POS)
delays the corrections from either channel and allows adjustment for an off-
center listening chair or for asymmetrical speaker placement.
The ideal setup for Panorama is an acoustically dead room, with speakers
well away from the walls, and the listener on the center line between the
speakers. The effect is diminished by reflections from nearby surfaces.
Furthermore, if the listener sees the two speakers from different angles their
responses will differ. The addition of acoustic absorption (soft furniture,
carpets and drapes) or diffusion (furniture or books that form irregular
surfaces and break up reflections) and time spent shifting speakers and
chair into more precise alignment (use a tape measure rather than relying
on your eyes) will all be rewarded.
Find a mono source, such as an announcer on FM radio or a mono film, and
listen for a tightly focused center image of speech or singing. If the image
is off-center, adjust the CP-1's BALANCE control. (The narrower the
monaural image, the better Panorama will work.) Perform the following
setup from a relaxed, comfortable position in your listening chair with your
head facing the center point between the speakers.
1. Reduce the volume to about -20 dB. If the display reads: PRESET at the
top left, push Program button 2; if not, push BANK, then button 2 to load
PRESET PANORAMA WIDE. Push PARAM eight times (until the
display reads: CALIBRATE OFF). Push PARAM UP to turn on the left-
channel calibration signal.
2. The test signal should appear to come from off to your left side, well
beyond the left speaker, with near-total silence in the right ear. Still
facing forward, move your head from side to side until the effect is
strongest. If you can find the sweet spot from the confines of your chair,
go directly to step 4; otherwise perform step 3.
3. Push PARAM once so the display reads: LISTENER POS. Push PARAM
UP and DOWN until you hear the strongest effect. Then push PARAM
four times, or until the display reads: CALIBRATE LEFT ONLY.
4. Push PARAM UP until the display reads: CALIBRATE RIGHT ONLY.
Again, shift your head from side to side to find the sweet spot, this time
looking for the point where the silence in the left ear is deepest. Compare
the locations of the two sweet spots from steps 2 and 4. If they coincide,
Calibration of the
Panorama Program
SPEAKER ANGLE is the angle be-
tween the main speakers as seen from
the listening position -here it is about
Select Panorama; Push PARAM to
display: CALIBRATE; then push
Param UP to: ON LEFT ONLY.
Move your head from side to side to
find the position where the noise is
full left, and the right ear hears noth-