Hi,
I’m trying to use an external hardware synthesizer to record the audio signal together with the MIDI data in real time via a separate MIDI interface and the audio interface used in Cubase. I want to monitor myself externally in real time via an analog mixer in front of Cubase. This is because I’m very sensitive to small latencies and want to be able to record properly even with a power-hungry project (high buffer size).
The problem is basically in the placement of the wave file in the Cubase project. Depending on the setting, it is sometimes placed too early and sometimes too late.
– To ensure that the audio played in real time ends up in the right place directly from the audio interface, I have not seen any other solution than to activate the “Take recording latency into account” mode. (Although even after speaking to Steinberg Support, it’s still not really clear to me whether the recording offset that you can enter is related to the “Take recording latency into account” mode?). It seems to work somehow.
But it is of course very complicated. I was able to solve the problem in Ableton Live. They recently added a “keepLatency” switch.
– In order for the audio file to set the wave file correctly when playing back the recorded midi notes, I now have to feed the audio channel on which I want to record the audio signal from the synthesizer from the “external instrument”. Then the wave file ends up in the right place, where the midi note is also located. Somehow logical, but in the end it doesn’t work for me 
I now have a workaround where I record the audio signal directly from the audio interface when playing in real time and not from the “external instrument”. Otherwise the wave file is set too late. I measured and set the “delay setting” of the external instrument to 15ms using audio loopback. But as far as I understand, this is only for playing MIDI data from Cubase, not for playing in real time. (That’s where I got confused.)
To summarize again: I want to control a hardware synthesizer from a MIDI keyboard that is rooted via Cubase and record the audio (plus MIDI) in Cubase. Listen to the audio directly in real time via an analog mixer. Then record this as MIDI and audio in Cubase. At most, play the edited MIDI from Cubase afterwards and record the audio again in Cubase.
In my opinion In my opinion, it is the only really sensible way to play external synthesizers in real time with Cubase. I hope you understand my complicated explanation, you probably know that it is not that easy.
I would be very happy to receive an answer.
Edit:
To be able to reproduce the recordings, take the following setting from SS 1 and 2.
Edit2:
Based on your audio interface specs, of course. (Visual measuring in the wave editor)
Best regards
Ron