I have a Yamaha dtx402k electronic drum kit. I have it connected to Scarlett Solo Gen 2 interface with Cakewalk. All my drums register while playing (including the kick/base drum) and when I listen to them back I can hear them all except the base /kick drum. I can see the base/kick drum recording on the midi track but no sound comes out, but all other toms, snare, cymbals do. Very strange. Any Ideas