I used to sell the RA30s a long time ago. I think the technology was the same sound source as the E20 and E30 keyboards which used LA Synthesis technology which was out of the D50 days. A very short sample at the beginning of the sound followed by a synth based sound tailing off. I don't recall the sound canvas sounds being used in this module. That happend when the RA50 and RA90 came out later.
George Kaye
Kaye's Music Scene
Reseda, California