I think Roy Haynes was playing Slingerland drums in the early/mid-60's. As rumor has it, around that same time, Roy had purchased a small sports car (an Alfa, perhaps?) Anyway, in order to fit his 18 X 14 bass drum into that car, he started using an 18" floor tom hoop on the front.
In 1964, Slingerland officially released their new "Jet" kit -which, coincidently had an 18 X 14 bass drum with TWO metal floor tom rims. I can only speculate to say that this was inspired by Roy Haynes' personal modification.
But then, somewhere between the release of the Jet kit in 1964 and 1966-7, something happened that caused Roy to jump ship and switch from Slingerland to Ludwig. ($$$$-?) And, also coincidently, that was the year that Ludwig released the Jazzette kit -which had the more "finished" look of a regular bass drum -except that the Jazzette bass drum's depth was reduced from the industry-standard 14" depth, down to its signature 12" depth. But, why?
My thought is that Ludwig did that to accommodate Roy and that the entire "Jet" and "Jazzette" kits were both specifically built because of him. Even the names "Jet" and "Jazzette" are similar! I think it all boiled down to Roy getting a smaller bass drum to fit his car!
Could it be that Bud Slingerland and Bill Ludwig were that competitive during that time? I think.....YES!