This lesson by John Mayer works for Jammr. I tried the idea with Casper today. Once I got him to calm his guitar playing down to match his vocals and serve the minimalist loop I had laid down; wow! It was a very rare jam that allowed me to increase my monitor volume rather than be repelled by the wall of harmonic hell experienced in most jams. More people should think about this. It increases the enjoyment factor and leaves room for more jammers. It does lay bare your chops. That's a good thing.
https://www.youtube.com/watch?v=D7j-7hoiNaY&pp=sAQA