Gilderfluke&Co 16 Bit CD-Quality Digital Audio Systems - Manual (Page 13)

pansion card on each AB/DR-3000 at one time. As of this writing, 175 MByte FLASH cards are (or soon will
be) available. These potentially give you instant access to up to 701 MBytes of memory. This translates
into almost nine hours of CD-quality audio storage on each MCRD-4000 equipped AB/DR-3000.
These AB/DR-3000s access their memory in sixteen bit wide words. For this reason you will always
need to use an even number of Eproms on all AB/DR-3000s. PCMCIA cards are sixteen bits wide, so they
can be added one at a time.
The AB/DR-3000 can support any type of EPROM memory chips from 27C040 (four Mbits or 512
KBytes) up to 27C080 (eight Mbits or 1 MByte). Note that all memory chips used with our AB/DR-3000s
must use ÔCMOSÕ technology. These use far less current and generate far less heat than the older
ÔNMOSÕ technology. CMOS memory chips can be recognized by the letter ÔCÕ following the numbers Ф27Х
in their part numbers. Luckily, the older NMOS technology is pretty rare in these higher density memory
chips.
D IGITAL A UDIO B US :
The DR-3000 includes a powerful mixing bus that can be used to send audio signals between all the
DR-3000s in a set of interconnected card cages. There are 120 time slots available on the Digital Audio
Mix Bus, divided into two 60 channel ÔbanksÕ. Any DR-3000 can be configured to use either the first or
second 60 time slots, but not both. One ÔhiddenÕ channel from each bank is reserved for internal use by
the DR-3000s to relay GROUP START commands to all the other cards within the cage. Any single DR-
3000 can use up to four of the following functions:
1) Listen to any one time slot, and mix the audio signals found there into the left or right output
channels of a DR-3000. The ÔlevelÕ of this signal can be permanently fixed, or adjusted dynami-
cally using:
a) 0-10 volt analog voltage inputs
b) DMX-512 input
c) RS-422 serial port
d) AB/DR-3000Õs front panel
2) Send the left or right DR-3000Õs repeater or output to any one time slot. The ÔlevelÕ of this signal
can also be permanently fixed, or adjusted dynamically using:
a) 0-10 volt analog voltage inputs
b) DMX-512 input
c) RS-422 serial port
d) AB/DR-3000Õs front panel
A simple example of the use of the Digital Audio Mix Bus would be where you have an installation
with a number of audio point sources with their own speakers, and a single background audio track that
you want to send to all the point source speakers. The background track would be sent to one time slot
on the Digital Audio Mix Bus and all the point source DR-3000s would then be told to listen to this time
slot. The background audio track is then mixed into all the point source outputs. The levels can be fixed
or configured to follow an external command.
A second example of the use of the Digital Audio Mix Bus is where you need to ÔchaseÕ an audio sig-
nal across a room to simulate movement. A single track on a DR-3000 can be used for the source sig-
nal. Its output would be sent to a single time slot on the mix bus. Additional DR-3000s or DR-4000s would
then be used to receive the signal by listening to the same time slot. An external signal from an
Animation Control System would then be used to adjust the volume on each of the DR-3000s to ÔchaseÕ
the audio across all of their speakers.
Other possible uses for the Digital Audio Mix Bus are:
¥ Implementing simple 'non-zoned' Public Address systems.
¥ Monitoring the audio in an attraction by feeding a number of audio tracks to a single monitor
speaker.
¥ Sub-woofer and multi-amplifier applications where the outputs of a number of DR-3000s are
fed to a single specially filtered output channel.
The Public Address system also uses sixteen of the time slots on the Digital Mix Bus from the first ÔbankÕ.
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