Sonny's been through at least three, probably four or five, different "tonal phases" since his return in the 70s. They've all, however, been distinguished by what can only be described as a huge sound. The rasp has come and gone and come and gone etc.
I remember when Sonny was on a Down Beat awards show on PBS ca. 1975 (Soundstage again). A bunch of us were sitting around watching that, and he did a duet w/McCoy on "In A Sentimental Mood" that was just awesome, but was also full of that rasp. Overflowing with it, in fact. The others in the room only knew of Sonny from the 50s and were more than a little, uh....perplexed by what they heard. Finally one guy said, with no small amount of befuddlement, "sounds like he's trying to imitate Archie Shepp".
Oh well....
If you like this one, try The Cutting Edge. That one is lively and frisky and has rasp out the wazzoo.