Hi, I just got a KeyStep 37. I've been working on a song using my old Yamaha MIDI keyboard with GarageBand. Now I'm trying to add to it with the KeyStep but suddenly the sound I'm using doesn't sound the same. I'm trying to play C and B at the same time and it won't do it. It picks one note or the other, but won't play them at the same time like a chord. But it plays fine on the Yahama. Any idea what's going on?