If I wanted to run an app to trigger samples via midi while MG2 is running would this be possible? How would the apps distinguish which midi message is for them if they are both “listening.” Is this a scenario where something like AUM would need to be used as the plugin host instead of MG2?
There are several ways to do it. But yes you need a host software platform. It could be a DAW or a free host like VST Host. You put your sample player in there, probably using something like sfz player or sforzando as the sample player.
The easiest way is using a pedal or some other method that is going to output MIDI. I describe that below. But if you want to have midi guitar trigger a sample when you play a specific note, you can do it but it’s a little complicated.
You put MG2 in that host, on another track or channel. In the host you have to route the midi guitar’s midi output to the sample player. Then you have to set the midi command on midi guitar that’s going to trigger the sample. If you decide it’s going to be a certain note, then you need to change that note into a command. You do that by using a midi filter, which changes a note into a command the sampler can recognize…usually that is a program change or a midi CC command. Sometimes your host has that midi filter natively. If not there are some free plug-ins you can use, if I recall midi ox does that. So you just insert the plugin on the same track/channel as midi guitar…typically you just insert it in the effects rack of the track.
Then you use the midi learn function on the sample player to trigger the sample when that command is received. This is where the sample player “distinguishes” which command it recognizes, per your question.
Alternatively, if you have some kind of a pedal that spits out MIDI, you can bypass all of that stuff and just send a specific midi command direct to the sample player. Your host or sample player may have a midi learn function so you can see what signal the pedal is sending, and then you just assign it to play the sample, in the sample player. If not you should still be able to assign that command to trigger the sample, check the manual for the sample player.
I use an outstanding Host made for gigging performers called Cantabile, but it’s insanely affordable for what it does. That software not only has all the many filters and what not, but I can send midi commands in a multitude of ways, including using a backing track and a specific point on that time line, or from a pedal, a note, basically anything that puts out MIDI. It’s actually pretty easy, once you get the hang of it. Good luck!