i ran a lyngdorf 1120 with my 1.7i’s (just for fun, to try it, and i really liked the pairing) but then i went to 3.7i’s, and then, got a 3400 to drive them
in terms of power, i thought the 1120 was just enough for the 1.7i’s ... my room is medium size (19 x 17 x 9.5), well damped and i don’t play super loud... 85-88 db peaks - i would think the 2170 would be plenty powerful 1.7i’s for most listeners with average size rooms, of course if the room is lively it will sound a little louder with the same power - but with my going to 3.7i’s, i wanted more headroom, so went to the 3400, which also streams roon directly like the 1120, which the older 2170 won’t do
i think room perfect is a wonderful feature, made a real difference with the 1.7i’s --and a HUGE difference with the 3.7i’s -- which i think is a touch too much speaker for my room, and excites some room modes, which the r-p feature handles beautifully - it is very cool the r-p correction can be toggled in and out, and the difference it makes can be heard very easily