Watch the Sub III Minor for I Major online guitar lesson by Robbie Calvo from The Modal Alchemist
In this example I'll be improvising with a C# minor 7 arpeggio over an A major 7 chord. There is one note in the C# minor 7 chord that doesn't occur in the A major 7 chord, so we are going to add that note to the chord. The note in question is B and if we add that to our A major 7 chord we'll get an A major 9.
The backing track is a chord jam using an A major 9 chord, so, we'll be able to target all of those cool tones with our C # minor 7 arpeggio substitution plus we'll get the 9th as a sweet note too! Rock on!
You can also use your C# minor pentatonic scales too! Why? Because a minor pentatonic scale is a minor 7th arpeggio with an added 4th, so why not!