
As you can see, the point is to stick to the same base note (1 or 2 octaves below what you'd expect) and then use command 17 to pick which note in the scale you want. Use the same base note for all instruments across your song. It doesn't have to be C though.
Techno babble: What happens here is that matilde takes the frequency of the base note, in this case 130.81 Hz, and multiplies it by the value you specify.