I know this is an issue that has a fix I just don't know what it is. I'm running Logic 9 on a MacPro with a Mackie HUI & an M-Audio Axiom 61 with an M-audio MIDISPORT 2x2 making the connection to the mac. So, if I"m working at home with Logic I have no issues...but the minute i bring the session to the studio, my instrument tracks start to drone if I dare select a track and hit a note. The drone can be described as a pinging sonar at about 200 Hz. I know there is something in the MIDI setup to correct this. Anybody have a clue? thanks p.s. Logic also shares the Mac with Pro Tools HD3 Accel system. I use the same MIDI setup for it. I only launch one program at a time.