VOTE: llcon
Late to the club, sorry. I also have had that problem with the Scarlett 2i4. I run Ableton Live and also hardware synths. All signals come together in a dedicated mixing console. I made it work this way: Ableton Live out through Scarlett Outs 1+2 into my mixing console. Stereo Outs of the mixing console (with hardware synths) into Scarlett 1+2. In Jamulus: Ins 1+2, Outs 3+4