What Song, Album or Genre do you use to set up your speakers ?
Well I truly love all types of music so I'll go through quite a variety, from electronica, disco, rock, funk, jazz, classical, folk, world...you name it. If I'm auditioning a speaker I put it through all those genres.
But for setting up my speakers I have some go-to tracks I've been using since the 90's simply because I know them so well and they have to sound right or I'm not going to like the speaker. One album I use is Everything But The Girl Atomic Heart, the first track. It has acoustic guitar (that has to sound right - clear, golden, sparkly - stand up bass -has to sound woody, deep but not flubby - vocals, percussion. It's also not a perfect recording, with just a slight bit of sibilant emphasis and even a slight bit of distortion. It really helps me know how a speaker handles that kind of thing - is it going to tear my head off and make it electronic and unlistenable? Will it disguise the flaws? Best is when I can hear the flaws, but it's not aggressive and the essential beauty of the recording comes through. That's what the Thiels do. I know where everything should be in the soundstage as well.
BTW, although I go on about how great the Thiels are in this thread especially, I found out long ago that it's very unlikely I would stick with one speaker. As we know there's no perfect speaker and I can get restless. Even just hooking up my older Hales T1 monitors to my 2 channel system, as I did recently, reminded me of what those speakers do so magically, that even the Thiels don't quite do. The Hales have a Harbeth-like magic with vocals and a way of producing a rainbow of instrumental timbre that even the Thiels don't match IMO. If I had the space, I'd probably choose to own the old Hales T8 speakers over the Thiels, and almost bought a used pair before going with the Thiels. But the Hales are even more massive and I'm trying to downsize.
I'm sure I'll end up with other speakers at some point in my aim to downsize, though in this case I doubt I'll actually get rid of both Thiels. I'll have to keep one of them.