Setting the audio channels from a Mac computer to play to the Dig Master L-R channels (channels 17-18)
The solution is within the Mac Audio/MIDI Setup preferences;
Your Mac should see the ZED-R's FireWire connections as two audio streams:
Stream1 = channels 1-16;
these route to the ZED's CH1-16 mono inputs
Stream2 = channels 17-26;
channels 17 & 18 route to the ZED Master L/R channels
channels 19-26 are 8 ADAT channels available via FireWire connection at 44.1kHz & 48kHz sample rates, where OS/software supports this.
To enable your Mac to play audio via the ZED-R's DIG MASTER,
you should configure your Mac's speaker preferences to use ZED channels 17 & 18.
With your ZED-R connected, configure the Mac's Audio/MIDI Setup prefs as follows;
1. Ensure ZED-R is selected for Default Input, Default Output and System Output
2. Click on the Configure Speakers tab, this will bring up the stereo & multichannel speaker options window.
There are two panes within the GUI. Above the top pane reads; "The ZED R has 26 channels in 2 streams".
3. Check the box next to the Stream 2 has 10 channels (17-26) option
4. Next, select the Stereo tab above the lower pane
5. In the lower pane; select 17 from the drop-down menu options under the left front tab
6. select 18 from the drop-down menu options under the right front tab
7. Click Apply at the lower right of the GUI. At this point, the Stream 1 has 16 channels (1-16) option should be un-checked.
8. Click Done to close the Configure Speaker GUI
Your Mac should now be configured to send stereo audio from the internal iTunes player to the ZED's DIG MASTER channels.
To send this signal (POST Master Fade level), to the ZED's Main L-R output bus;
Select the DIG MASTER TO L-R switch above the PHONES socket and adjust the L-R faders.
To send this signal to the ZED's CRM/ALT/MONO SPEAKER OUTPUTS;
Select the DIG MASTER (MAIN MIX L-R) switch below the PHONES LEVEL control and adjust the CRM LEVEL control.