You are in Realband Forum so I was talking Realband.
That DXi checkbox is what selects whether to use a default DXI (or VSTi) synth. You said earlier you didn't know where to check that.

"I've been trying to see if I'm inadvertently using a soft-synth (like GS- Wave Table) for MIDI. I'm not sure where to look or what to look for exactly"


I do not work here, but the benefits are still awesome
Make your sound your own!