Roland's SA technology is actually a precursor of their SuperNatural synthesis. This is from an Electronic Musician article from 2008:
"After the press conference, I talked with Toshio Yamabata, the director of
Roland R&D; Shun Takai, an engineer who has been working on the technology
directly; and Mike Kent, manager of technical relations for Roland
R&D. They confirmed that SuperNatural, which the company has been quietly
developing over the past two decades, is indeed an outgrowth of SA.
As was the case with SA, the first step in creating a SuperNatural program
is separating the various elements of the target sound—for example, the
string and bow of a violin as well as the frequency, time, and phase components.
These elements are then utilized to reconstruct the sound using an
additive technique with complex waveforms from the original sound, along
with modeled components and wave-table synthesis."