Notes: This article applies to users using LUNA with multi-unit Apollo configurations where the total number of available inputs and outputs (analog, digital, virtual, etc) exceed 64 channels each. Single Apollo configurations will always have less than 64 inputs and 64 outputs.
LUNA 64 Channel I/O Limit
Core Audio limits your total number of inputs and outputs to 128 channels each. If you are using LUNA with Apollo units in a multi-unit configuration, your total potential number of input and output channels can exceed 128. LUNA adds channels for all its unique features that run invisibly in the background. Due to this, it could exceed 128 channels if your max limit is set to 128 I/O. If using LUNA, It is recommended to limit your I/O to 64 channels to make sure you don’t exceed the 128-channel limit.
How can we work around this?
First, navigate to the I/O Matrix panel in the Console Settings window (Console > Settings > I/O Matrix). You will need to manually reassign the channels you want to access so that they fall within the first 64 channels in both the input and output columns. Typically, Apollo users will sacrifice either Virtual or Digital (S/PDIF, ADAT, or AES/EBU) inputs and outputs to make sure all of Apollo device’s analog inputs and outputs can be used when using multi-unit configurations.
How do we achieve this?
You will need to manually configure Apollo I/O on the I/O Matrix panel in Console Settings. First, change both the "# Inputs" and "# Outputs" options to "64" using the fields at the top right of the I/O Matrix page.
Setting "# Inputs" and "# Outputs" to "64" on the I/O Matrix page
If any inputs or outputs that you need to use were cut off by limiting the I/O to 64 channels, then you will need to manually reassign those inputs or outputs within the first 64 channels. First, click anywhere on the input channel you want to reassign. Select the device, followed by the channel type, followed by the input (see below). Please note that there is no “done” or “apply” button – simply click the “x” to close the window after making your assignment.
Selecting and reassigning an input channel
Selecting and reassigning an output channel
If there are multiple channels in a row that you want to reassign in sequence, you can use the Cascade switch to save time. Manually reassign the first channel you want to change, click the Cascade switch, then click, hold, and drag down from that channel. Release on the last channel you want to reassign. All of the channels you just dragged over will be reassigned in sequence starting from the first one you clicked on. Click the Cascade switch again to exit this mode. See the Console Settings chapter in the Apollo Software Manual for details on using the Cascade switch.
Repeat this process for all input and output channels that you want to reassign.
Using Cascade to reassign input channels in sequence
Once complete, you can save this setup as an I/O Preset for easy recall and switching by clicking the "Save" button at the top of the I/O Matrix page.