Audio Connections & External Instruments Setup Problem

I need some help with this. I have an RME Fireface UFX & PC

In Cubase’s Audio Connections, I have my Stereo In as Analog 1 & 2.

Stereo Out is Analog 1 & 2.

But when I go to setup an External Instrument, in this case a synthesizer, I select Audio Device as my RME device… but when I go to change the Device Ports, I get, “The selected device port is already used. Selecting the port for this bus will replace any previous connection.

I don’t understand that. I need the Device Port to be Analog 1 & 2, as well as the Stereo In.

I’d like for my external synthesizer to work whether I create an Audio, Midi or Instrument track.

Any help appreciated.


You can only designate your device port for one of the tasks. I assume you want to use input 1/2 as audio input. Then you first will need to delete your audio input (audio input tab) for that. Then you can use it for your external instrument. Or you can use input 3/4 if your audio interface supports this.

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Instrument tracks are not usable with external instruments, these are simplified combinations of one MIDI track and one VST instrument.

If it is used as “input” it is not usable as external instrument…

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Also you don’t need to setup your synth as an External Instrument to record with it. You can treat it like any other audio or MIDI source. The benefit of creating an External Instrument is that it will look like an internal Rack Instrument in Cubase. So you can change presets and modify other settings on the synth within the Cubase GUI - which is convenient. But the cost is that you have to dedicate an Audio Input to it. And also depending on the specific synth, some cursing may be required during implementation. But if you are content to use the physical knobs on the synth you can ignore the External Instrument setup.

Regarding the inputs on your Audio Interface, some folks don’t know that you can use the same physical input multiple times to create different busses. For example Analog 2 is used in 3 different busses below. So you could have your current ‘Stereo In’ buss plus another called ‘Synth Name’ both using Analog 1 & 2.

Hey Raino, thanks but how? If the same buss is selected it doesn’t allow me to use it multiple times

Can you post a screenshot of where it won’t let you do this. FYI you are not using a buss multiple times, it is the Device Port you reuse.

I would normally post an animated gif showing how to do this. But my DAW PC had a major meltdown & it looks to be awhile to get a new one built.

Perhaps we can entice @steve to make a quick example gif?