Yes Ols Ears it was a riot in the seventies in Hope or so they say. Actually if you can remeber the seventies then you probably weren't there! The seventies that is.... Or the sixties, eighties or nineties either. And BTW: the real answer is:
MWM = woofer (dual 15" horn loaded)
MWM-S = woofer (single 15" horn loaded)
MSSM = sub squawker (single 10" horn loaded)
MSM = squawker (4 x 1 1/2" VC compression drivers manifolded onto horn)
MTM = tweeter ( array of piezo horns)
MMTM = cinema tweeter that pierced like a laser beam (4 x K77 tweeters mainfolded onto two horns)
P Wilbur designed the manifolds which when completed was an audio engineering feat but as it was a "pro" (we called it "industrial" back then) product this feat was hardly recognised by audiophiles. Not only did the manifolds work but how they were made was yet another engineering feat.
Were you there at those initial tests? If so then we probably know each other.