AWB's on a Blu-ray, not an SACD, are you 100% sure you're playing the disc correctly?
the Quads that came out of Sigma are indeed the crème de la crème, my personal gold standard of Quad, although Joe Tarsia was only ever credited as mixing one Quad, MFSB's "Love Is The Message", it's absolutely a great Quad but let's not overlook that he had a team of talented engineers including Don Murray, Jay Mark, Carl Paruolo & Arthur Stoppe, who mixed all the other totally wonderful Philadelphia International Quads (they're all "10" in my book, too!)