I don't know if this is the right place to be asking this, but giving it a shot!
I'm using Mainstage 2, and I want to make a patch that has two layers/instruments. When I say "layers" I mean that two sounds/instruments should be triggered simultaneously when a key on the keyboard is pressed. The idea being to play both lead and bass notes with just one key. The problem is that the bass isn't playing just one octave lower, it's playing more like 15 semitones lower. But if I tune the bass synth 15 semitones down it will sound OK on some notes but not on others.
The reason for this is of course that the bass doesn't follow the scale that the lead is played in, because the synth doesn't know what scale it is..
So I'm wondering if there is a way to make the bass "follow" the scale that the lead is played in?
Edit: Example:
The lead is
D A B - B D C# - These are the keys I'm pressing on the keyboard, and then I want the bass to play
B F# G - G B A - one octave lower. The scale is B minor.