I heard my computer monitor speakers which had a picture video of Bose 901's.. But not to fear. I heard them in 1978 when I bought my 1str relatively hi end system. We A/B"d the 901 against the Original large Advent. I went home with the Advents.
Now its true that the901's sounded pretty decent at very high volumes. But The Advents sounded better at every volume level I generally listened.