Bose AV28 Manual page 18

Although the AV28 is a 2-zone audio system, as discussed, the clocking limitations of the hard-
ware occasionally restrict which forms of audio can be simultaneously played out the two zones at
a given time. In these situations, Zone 1 (assumed to be the primary zone) would be allowed to
play the digital source while Zone 2 would be downgraded to playing an analog input source. For
example, a user could not play a DVD video disc in Zone 1 and simultaneously listen to the exter-
nal AUX digital input source in Zone 2, since the CS98K's PCM output port can only clock out a
single digital stream at a time. The system, in this case, would use the CS98K to decode the DVD
video disc's audio for Zone 1, and would select the external AUX analog inputs to play in Zone 2.
The following tables describe the resulting audio formats when playing each combination of
sources simultaneously in the two zones:
TYPE OF AUDIO INPUT ALLOWED TO PLAY OUT EACH ZONE
(Zone 1 result shown on top in bold, Zone2 result shown on bottom in italic)
Off
Off
Off Off
Off
AM Analog
Off
FM Analog
Off
Tape Analog
Off
AUX Analog
Off
VCR Analog
Off
TV Analog
Off
DVD Digital
Off
MP3CD Digital
Off
CD Digital
Key: Zone 1 performance has
been downgraded to
support Zone 2.
As shown, for consistency, Zone 2 speaker outputs generally only plays the analog external inputs
(AUX, TAPE, VCR and TV). The exception here is when both Zone1 and Zone2 are listening to the
same external input; in this case, both zones will play the external digital inputs (if present), to
ensure that audio-path delays are identical for each zone.
When an external input source (AUX, TAPE, VCR or TV) is chosen for Zone1, the AV28 automati-
cally checks for the presence of a digital input stream and plays it if it exists. If it doesn't, the AV28
will default to playing the analog inputs.
Theory of Operation
Source Selected for Zone 1
AM FM Tape
Analog Analog Digital
Off Off Off
Analog Digital
Analog Analog
Analog Digital
Analog Analog
Analog Analog Digital
Analog Analog Digital
Analog Analog Digital
Analog Analog Analog
Analog Analog Digital
Analog Analog Analog
Analog Analog Digital
Analog Analog Analog
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Zone 2 performance has
been downgraded to
support Zone 1.
AUX VCR TV
Digital Digital Digital
Off Off Off
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Digital Analog Analog
Digital Digital Digital
Analog Digital Analog
Digital Digital Digital
Analog Analog Digital
Analog Analog Digital
Digital Digital Analog
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Not allowed because the tuner cannot play
AM and FM simultaneously, or because
only one disc can be in the tray at once.
18
DVD MP3CD CD
Digital Digital Digital
Off Off Off
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital Digital Digital
Analog Analog Analog
Digital
Digital
Digital
Digital
Digital
Digital