Gilderfluke&Co 16 Bit CD-Quality Digital Audio Systems - Manual (Page 10)

Each DR-3000 or AB-3000 is a complete stereo audio source. It can be used as two separate mono-
phonic repeaters, or as a single stereo pair. Any number of DR-3000s can be plugged into one or more
card cages to provide any number of simultaneous audio tracks. Any number of DR-3000 repeaters can
be synchronized within 1/44,100 of a second for use as a multitrack bin loop tape deck replacement.
Multiple bin loops as well as independent repeaters can all be operated within the same card cage.
An AB-3000 is identical to a DR-3000, but comes in its own case and includes a power supply. It can
be mounted anywhere you need just one or two CD-Quality audio tracks. All you need to add are ampli-
fiers and speakers. All configuration and commands for the AB-3000s are identical to those for the DR-
3000 Repeaters. An AB-3000 just wonÕt respond to commands for features for which it doesnÕt have the
necessary hardware. An example of commands that the AB-3000 canÕt use are those for the PA system.
You can record a sound into a AB/DR-3000 yourself, or send us a tape to do it for you 4 . A recording
of the sound is first recorded into an IBM compatible or Macintosh computer that has a some sort of six-
teen bit audio sampling hardware installed. The audio card in your computer takes your original audio
and turns it into digital computer data. This is stored in one of several industry standard file formats on
your computer. On an IBM compatible this will be a Ô.WAVÕ file. On Macintosh and Amiga computers an
ÔAIFFÕ file format is used. Most audio editing systems can generate these file formats directly. Sample
rates supported on the AB/DR-3000s are at 11KHz, 14.7KHz, 22KHz and 44.1KHz for audio reproduction at
bandwidths of 10 Hz to 5 KHz, 6.5 KHz, 10 KHz or 20 KHz respectively
5 . Sixteen bit linear encoding gives a
dynamic audio range of 96 dB, which is identical to the sound quality from a Compact Disc (CD).
Once sampled, the .WAV or AIFF file is run through a small program which we provide to convert it
into the format the AB/DR-3000s can use. This program allows you to select from all the .WAV and AIFF
files on your computer to decide which ones will be loaded onto each AB/DR-3000. Up to 255 different
messages can be loaded onto each AB/DR-3000 card
6 . You can set the amount of compression you
would like to use, and how low a level signal to use when doing silence evaluations. The compression
uses an algorithm similar to DolbyÕs, but with extensions to stop using any memory at all if an instant of si-
lence occurs. The data compression alone gives you about a 4:1 reduction in the amount of memory a
sound needs
7 . The silence removal can extend this even further.
The program compresses the data and divides it up into appropriately sized and formatted files for
use by the AB/DR-3000s. These files are then 'burned' into computer memory chips using a commercial-
ly available EPROM programmer, or sent to appropriate PCMCIA memory cards. These are then plugged
into the AB/DR-3000s
8 . From this point on, the AB/DR-3000 can play back the sounds that have been
loaded onto it. Any of the different messages can be instantly accessed through the optoisolated inputs,
serial port or DMX-512 input. Any spiel on any card can be played through once or looped so that it re-
peats. Mono recordings can be directed to play through either the left, right or both outputs. You can
even play a mono recording out of both AB/DR-3000Õs outputs asynchronously. This is useful on long ve-
hicles (like trains) where the same message must be played for the rear half of the vehicle at a slightly
later time.
Although 'data compression' saves the amount of memory you need to use, it makes it darned diffi-
cult to estimate the number of Eproms your recording will need until it has been digitized. The following
charts show the capacities with a variety of sounds using different sized Eproms:
G ILDERFLUKE & C O . ¥ 205 S OUTH F LOWER S T . ¥ B URBANK , C ALIF . 91502-2102 ¥ 818/840-9484 ¥ FAX 818/840-9485
2
4 Tapes can be sent on DAT (this is the preffered medium), cassette, 1/4Ó reel/reel, CD or video tape.
5 No matter the sample rate used, the AB/DR-3000 reproduces the sound at a full 44.1KHz update
rate. Because of this, and the lower efficiency of the compression at lower sample rates will give you, we
recommend that 44.1KHz samples be used in the majority of applications.
6 These individual messages are refered to by the industry standard term 'spiel' in this manual.
7 The actual compression ratios uou get depends on the sounds you are compressing. A clean
recording from a digital source will compress much better than one from a noisy recording.
8 A PCMCIA card requires a MCRD-1000 or MCRD-4000 installed on the AB/DR-3000 to hold it. A spe-
cial card is available which allows a PCMCIA hard disk drive to be used.