Ahh I follow now! So ideally one would route all channels through an interface that can support those channels and then send the signal to external amps to fix the delays to every channel.
I see my AVR has a max delay of only 20ft between channels.
Just ran the test. Two legs to the measurement setup are as follows:
1 -> OpenDRC-DA8 -> ch 1 -> Cosmos ADC L
2 -> OpenDRC-DA8 -> ch 2 -> MOTU M4 analog ch 1 input -> CamillaDSP -> MOTU M4 analog ch4 output -> Cosmos ADC R
At first I tried to do 96 kHz, 512 chunk size and no resampling however without resampling I would often get a capture error saying I was providing an invalid argument. It always worked with BalancedAsync resampling enabled.
For a given session I could dial in a delay that would perfectly sync the two channels but if I restarted CamillaDSP or the RPi the delay changed. It was always between 13-15 ms which was lower than anticipated but the variability of the delay after restarts would be a no-go for anything relying on phase matching.
I had anticipated that the relative delay might shift during a given session as I would see buffer levels changing but in practice no delay shifting was observed on the output which was very nice.
Michael