Question

When I connect a Roland XP-30 through Midi/USB cables, Studio One shows a signal is received, but there is no audio heard.

Answer 1

If you are trying to record the audio output from the XP-30 you'll need to plug the audio outputs into your digital audio interface.

I looked at a couple pages describing the unit and couldn't see any indication that it was or includes a digital audio interface.

When you say that Studio One shows a signal, is that on an audio track or a MIDI/Instrument track?