Playing air guitar ? Sorry couldn't resist.
I think it's quite logic that there is no other solution than that.
Because the RTL over USB is always much higher compared to converter latency and forwarding audio locally on UCX II from input to output port. Additionally latency over USB can become quite high depening on the buffer you configure.
And here you have USB two times (PC <-> UCX II and PC <-> Guitar Processor).
Then you have additionally a little latency by the processing of loopback application and finally you will have to route the different audio flows in the DAW for monitoring.
So you have always this flow for monitoring
Aggregate Device /
+---- Loopback Application ----+
USB (around 4ms) USB (around 4ms) latencies over USB depend on configured buffers (*)
UCX II Guitar Processor
| D/A conversion
(*) I only want to demonstrate, that you are here most likely already in the range of around 10ms
Fireface UCX II (audio flow for monitoring local on the UCX II)
Time for AD + DA conversion at 44.1 kHz: around 0,11 + 0,13 = 0,23ms (plus maybe a few samples through the digital matrix on the UCX II).
And now pls tell me how to avoid all this latency if not connecting the guitar processor directly to the UCX II?!
I think there is no other solution than that.
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