Still trying to build the chops. I find that after a tem minute warm up of low tones and octave slurs, my mid staff notes have a fluttering that I really have to concentrate on to stop. I have been using a Bach 5C and today, I tried the Bach 7C that came with the Yamaha 2320 I use. There is no discernable difference that I can tell. Will this go away with practice or do I try some other MPs?