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Prism Sound ADA-8XR Multi-channel A/D D/A Converter Module Reference - Revision 1.01
© Prism Media Products Limited, 2001-2005
Page 3.38
per-channel basis. For more information about the operation of the ADA-8XR’s Overkillers
see the ADA-8XR Operation Manual.
7.8.6 Identify I/O
Clicking the ‘Identify’ button on the Hardware Setup dialogue box identifies an ADA-8XR (or a
pair of ADA-8XRs emulating a single 192 I/O) by lighting all its front-panel LEDs, in the same
way as for a 96 I/O or a 192 I/O.
7.8.7 Miscellaneous
Analogue input and output line-up levels of the ADA-8XR are not controllable from the Pro
Tools|HD user-interface. They are precisely controlled in software from the ADA-8XR menu
system, and comprise a nominal and a trim component per channel. Thus the ‘Input Trims’ in
the ‘Analog In’ tab of the Hardware Setup dialogue box and the ‘Output Trims’ in the ‘Analog
Out’ tab do not function. Since analogue line-up more commonly depends on the connected
equipment rather than a particular session, it is usually an advantage to be able to recall a
session without overriding line-ups. If a variety of line-ups do need to be stored and recalled,
this can be done using the ADA-8XR’s Store system providing that recall of analogue line-ups
is enabled. See the ADA-8XR Operation Manual for more details of this.
Settings to do with digital I/O formats not supported by the ADA-8XR obviously do not
function. These include the ‘Digital Format’, ‘S/PDIF Format’, ‘Port Settings’ and ‘Ext Clock
Output’ settings on the ‘Main’ tab, and the ‘Input Format’ and ‘SR Conversion’ settings on the
‘Digital’ tab of the ‘Hardware Setup’ dialogue box.
7.9 Analogue Line-Up Nomenclature with Pro Tools
Some confusion may result from the different nomenclatures used in the ADA-8XR and Pro
Tools systems for expressing analogue line-up levels.
Pro Tools sets its analogue line-up by reference to ‘headroom’ above a nominal operating
level of 0VU (+4dBu). The ADA-8XR’s line-up is specified in terms of the dBu equivalent of
full-scale digital (0dBFS). So, for example, to set a line-up on the ADA-8XR equivalent to
‘14dB’ in Pro Tools nomenclature, it is necessary to set 18dBu on the ADA-8XR (+4dBu +
14dB).
7.10 Using the ADA-8XR with Digidesign Interfaces at high sample rates
This section concerns issues related to the use of the ADA-8XR in Pro Tools|HD systems
alongside Digidesign 192 and 96 I/O units at sample rates of 88.2, 96, 176.4 and 192kHz. A
scheme by which ADA-8XRs and 96/192 I/O units may by synchronized using a combination
of Loop Sync and Wordclock at the higher sample rates is described.
7.10.1 Sync differences between the ADA-8XR and Digidesign interfaces
I/O units in Pro Tools|HD systems are synchronized by means of a Loop Sync whereby all
interfaces in a system are connected in a ring using BNC cables. The synchronization signal
takes the form of a TTL-level square wave similar to a Wordclock. One of the interfaces is
nominated by the application ‘Hardware Setup’ dialogue as the master, and this interface
outputs the synchronization signal on its Loop Sync output. All the other interfaces
synchronize to the clock on their Loop Sync input and also repeat it on their Loop Sync