Hint:

If you hear a flanging or doubling effect when playing from your MIDI controller, it’s most likely because the controller is playing the sound directly in addition to MIDI Thru data being routed back to the controller’s sound module. You may opt to turn MIDI Thru “off,” but another option is to send a Local Control Off message (via the Instruments Mixer window). This will cause the controller to become disconnected from its internal sound module and only play upon receiving external MIDI data.