In '76 and in Japan I purchased two pair of Bose 901 Series II, if you recall four channel was all the rage. Also got a Teac A-3340-S (4 channel) and two Sansui AU-20000(s) @ 170 watts a channel. Well, 680 watts into the Bose back in the day sounded fabulous. Still have the 20000(s) but due to age they both will not come out of protection mode. The Bose got sold along the way.
About 6 years ago I saw an ad for a factory refurbished pair of 901 Series VI for $500. Took the guy up on his offer and amazingly they were in sealed factory cartons and all nine drivers (each) replaced with the latest version. Bose were known to have the foam surrounds deteriorate.
For all you Bose haters, here's a clue...play them backwards! Such that the 8 drivers in each speaker are facing the listener. BTW Bose does make an 801 that is used for sound reinforcement that lacks the ninth driver on the opposite side.
Mine are in my "concrete vault" as I refer to my 1000 sq ft garage. And I can say is that there is no slap echo, they sit on top of a steel shelving unit near the ceiling and will shake your teeth loose. Much to your surprise they do an amazing job and not just on Robin Trower or similar metal. Dianna Krall and Patricia Barbara both sound great. That is until you go upstairs into the music room and listen to the real deal.
Love 'em or hate 'em that's on you not me.
Regards,
barts