How to switch audio signal from a single recording input between 2 Ardour tracks in runtime?

I am using UbuntuStudio 19.04 with Ardour 5.12 Recently I learned how to run Windows VSTs on Carla so I can record clean guitar directly into an Ardour Track (with echo and chorus plugins) and also thru MIDI Guitar 2 to send MIDI notes to a second Ardour track with a synth plugin. Now what I need is a way to make to play thru one signal path at the same time and be able two switch on the fly during the recording as we want to make home recording of a live performance. For example I will play and record into track 1 in Ardour the clean guitar with no synth sounds then I need to switch in runtime to play some synth pads/strings with no guitar sound, maybe thru a program change messages from a button in a usb midi controller I have.

I know I can always record both and then cut the sounds I don’t need in post but honestly I want to do this for a recording of live performance so the performance should be as realistic as possible.

Any suggestions? Thanks in advance.

I don’t have an easy answer for you other than maybe doing a lua script on a bus to change routing, or if you can find an appropriate switcher plugin, a MIDI controller bound to a control? I believe that is possible, and then route from the bus to the two tracks as appropriate.

But if you are trying to capture a live performance, how are you switching during the performance? Why wouldn’t you handle this on the performance side and then record the performance? Normally this would be the standard, change between your sounds as a guitarist, and the engineer would capture the sounds (And reinforce or record as appropriate). This would be considered two separate systems.

If you want to combine performance, and engineering: You could write “mute” automation for both tracks.

That way Ardour records both, but you can hear only the unmuted tracks. The problem with this approach is there’s no switch to unmute one track and mute another in a single step. Mute is separate for each track.

You could use some cross-fade (A/B) plugin on a bus. To select what is heard. Assuming the both the Guitar sound after FX is stereo as well as the MIDI synth Guitar is: create a 4 channel bus and use “X-Fade” or “Crossfade” plugin. 4in, 2 out. Use MIDI remote-control and record automation for that.

In either case a MIDI CCs can be bound to to switch or toggle what your hear. while Ardour still records input as-is.

PS. I suggest to never rely on software written with only the Windows as platform in mind, as part of a workflow on an other OS.

Thanks Robin, I will try your suggestion, sounds like what I need. About your other suggestion, I always try to use native LV2 plugins whenever possible but I have not been able to find a Guitar (or sound) to MIDI plugin that is Linux native, any suggestion?