I have power to spare with my Thor's (Tyler's mid line qualifies in this benifit as well), even though my room is large I listen at low/mid volume. Speaker designs that use Seas drivers are rated as low efficient, like 87, but still a little 40 watt tube amp drives them with full rich sound, vol control between quarter/half power. Its like Star says on the Thiel topic, "nothing that dominates the room both sonically and physically". ...lets see I've got Debussy's La Mer on (a work that has recently been voted by some members over at Gramophone as a bit "over-rated", IOW, "out-dated"...????, I guess they suggest I listen to a Brahms' sym instead..??)...anyway the vol is at 10 oclock...now at 11 oclock. Its at this vol the KT90's show some weakness. A bit of stress shows up, steely sounding , which is why I keep it at 10 oclock, the sound is pure and clean. Also I might add La Mer has very soft passages and great cressendos, these climaxes can resonate through the house in which a cry will follow, "turn down the stereo!!!"...., so 10 oclock serves well. If the KT88's arrived and show up the KT90's in terms of crisper mids, , then I'm gonna wonder why Jadis even stuck the 90's in the JOR in the first place.
Hope I answered some of your question. There is no connection between low sensitivity / low volume being at odds. Also it should be said that the old myth that tubes can not deliver in bass and slam, is just that a myth, and not to be believed. As my little 40 watt Jadis blew out the water my Rotel 100 watts per channel ss amp.
