Once again, we must remind you: if independent (non-synchronous) AES/EBU sources are connected to the EC-1 card, audio cannot be monitored (or recorded) simultaneously since the clock for each input channel pair is independent. When monitoring AES/EBU digital audio from more than one channel pair, all of the AES/EBU sources must be synchronous, i.e., controlled by the same sample clock.
IF THE EC-1IS NOT INSTALLED IN THE MASTER M20:
If the EC-1 card is installed in a slave M20 (e.g. ID 2), the only clock source available will be ADAT (the clock coming in through the ADAT Sync In jack). In this case, AES/EBU input to the slave must be synchronous to the master (ID 1) M20 to avoid clocking problems.
This is where the use of synchronous word clock (or other applicable external clock source) into the master M20 is an appropriate solution.
Note: In typical scenarios where ADAT optical is used as the digital input source, the “D” indicators beneath each channel’s meter segments will remain solid to indicate that digital audio input for the selected source is present. If ADAT optical signal is not detected, the “D”s flash as a warning. When a valid external (synchronous) clock source other than I/O CARD (e.g. WORD CLOCK) is used with an AES/EBU digital audio input, the “D” indicators will always remain solid even though AES/EBU signal may not be present.
INPUT ROUTING USING AES/EBU (I/O CARD) AS THE DIGITAL
SOURCE
The Input Routing feature of the M20 allows you to go from any input to any track without the need for repatching. Just as the analog Input Routing feature allows you to do that with an analog input, you can do the same for AES/EBU inputs from the EC-1 card. AES/EBU routing accommodates a 2-, 4-, or 8-bus mixing configuration. You have the following AES/EBU routing choices when the digital source = I/O Card:
∙Odd/Even (2-bus feed): Press INPUT ROUTING and either the Track 1 or 2 button. Input 1 feeds channels 1, 3, 5, 7, and Input 2 feeds channels 2, 4, 6, 8. To record on an odd-numbered track, route the signal(s) to bus #1 or left. To record onto an even-numbered track, route the signal(s) to bus #2 or right. By simply putting the desired track into record, the proper signal will get there, even though it is not connected directly to the track’s input jack.
∙Half & Half (4-bus feed): Press INPUT ROUTING and either the Track 3 or 4 button. Input 1 feeds channels 1, 5; input 2 feeds 2, 6; input 3 feeds 3, 7; input 4 feeds 4, 8). To record on tracks 1 or 5, route the signal(s) to bus #1. Likewise, to record onto tracks 2 or 6, route the signal(s) to bus #2, and so on.
∙One-to-one (8-bus feed): Press either the Track 5, 6, 7, or 8 button in Input Routing mode. This is the power-on default, where each input feeds its corresponding channel. To record on track 1, send the signal to mixer bus 1, to record on track 2 send the signal to mixer bus 2, etc. This is also the recommended mode when feeding the M20 from a mixer channels’ direct outs.
