You definitely need to turn on background audio in all the apps, otherwise they will indeed not make any sound!
Each app needs to be configured separately to *not* listen to events from the samson directly at all and only listen to events from their virtual ports.
In particular the KORG apps can be tricky. I don't have iM1 but I assume it is like the other KORG apps in that it insists on listening to all MIDI devices permanently but luckily just on the MIDI channels it normally responds to (seems like channels 1-8 for tracks 1 to 8, from the manual). My suggestion to set things up to include control of the KORG app is as follows (and this will probably help with managing your other apps also)
1. Set the MIDI channel on the samson to channel 15. This way we can control which apps get controlled. This is mandatory!
2. Set the MIDI channels of Sunrizer to 9
, Magellan to 11
and Galileo to 13
. Configure all apps to run in background.
3. Switch to MidiBridge. If you play your keyboard you should expect to hear nothing now. If you do, then one of the apps is responding to events on channel 15 or your samson is still running on channel 1.
4. Assuming you have no sound (that's great) then we can start hooking things up and remapping channels to whatever channel each app is listening on.
5. Try with iM1 first. Connect samson (on left) to iM1 (on right) so there is a green line between them.
6. I am going to recommend using the 'Stream Byter' module to remap channels since it will remap all events (controller, pitchbend, program changes) as well as notes which will probably work out better:
- Touch the 'beaker' icon on the iM1 port on right and touch the (i) button on Stream Byter. Press 'On' and paste the following rule into the edit box:XX = X0
- press 'install rules' and then 'Done' and 'Done'
You should now hear iM1 responding to the samson if all went well.
Now you need to repeat steps 5 and 6 with the other synths but use slightly different Stream Byter rules depending on the synth:XX = X8 # sunrizer
XX = XA # magellan
XX = XC # galileo
All apps should now respond to the samson. You can then connect/disconnect routings on the main interface page to switch synths on/off.
Once you have mastered that you can think about splitting, layering and all that nice stuff and saving each setup into a Scene for recall. However, get the basics happening first.
I realise that iM1 has up to 8 separate tracks and magellan has 2 (not sure about the others). It will be possible to set things up so that these can be individually addressed also and I have left space in our channel mapping for that.
PS. I don't get many positive comments about MidiBridge's UI, so thank you. The UI makes sense to me and I did think carefully about it when I developed it, but general consensus seems to be that it is ugly! :-)