Although I won't get my audio interface until Monday, I did some more experimenting with my setup and found out a little more about the "unwanted sound" I keep getting. I'm hoping someone out there has come across it.

For example, when I isolate the bass track (and mute all of the other tracks), I not only hear the bass sound but what I can best describe as a high metallic repeated note (sort of like a drum roll) that seems to somewhat mirror the bass notes. In other words, if a single bass note plays, along with the bass note I hear that high metallic repeated note sound. When the bass note changes pitch, the high metallic repeated note sound also changes pitch. I have done this with other tracks (having only one track play while the others are muted), and no matter what track I have playing (with the other tracks muted), that high metallic repeated note sound is also playing. Since I have muted all of the other tracks, I can't seem to put a finger on where this sound is coming from.

Although I don't receive the message any longer, I noticed in the beginning that when I first tried to get sounds out of the TX81Z, I received some sort of "data full" message on the TX81Z. Maybe I'm having a midi feedback issue or something similar?