I have a Roland TD-4 E-Drumset and using the UM-ONE USB MIDI cable to connect to a MacBook Pro with the EZDrummer2 demo installed. The MIDI mapping works fine with all the drum parts with hardly any latency. The problem I am having is the output to my stereo receiver. My MacBook is connected to the receiver via the headphone jack. When I use my mouse to click on the EZ2 virtual drumset, the sound is fine. However, when I play the Roland, the sounds are extremely faint…..the cymbals are somewhat audible, but I have to turn my receiver volume WAY up to hear the snare/kick/toms. The odd thing is that when I plug in my regular headphones it sounds great. Any suggestions?