Auditioning speakers in a system other than your own requires that you know exactly what the music is like - you need to know it intimately. I personally do not think I make a major decision like speakers without a) putting them in my system before I bought, and/or b) being willing to sell them for a small loss if I did not like them - assuming that is the part of the cost of changing speakers.
As for what I have used in the past, I can recommend the following discs:
Ry Cooder's A Meeting By the River (lots of delicate tones, transients, and ambient noise); the above-mentioned RR discs of Eiji Inoue and the Minnesota Orchestra (Aaron Copland works, or Pictures at an Exhibition); a copy of Chopin Preludes (either Yevgeny Kissin or Maurizio Pollini); the Zubin Mehta recording (LA) of Holst's Planets or something similarly 'loaded' (instrument separation, clarity, ability to tame 'Saturn', and other dense passages without giving up the delicacy which is really there in good dense music); I also take along piano music which is more melodic (any number of things), I take along horn music which shimmers when done right (and for the last several years, that has been the 'French Music for Trumpet and Organ' by Hardenberger & Preston disc from bis), and I take along music with closely-miked stringed instruments (for me, the best way to get a grip on tone, and the speaker's ability to deal with all the ambient aspects (lots of stuff going on with this, just like there is with Chopin preludes). I also take along vocals, which is more difficult to deal with because I don't find female vocals the best way to test - for me, the interesting vocalists to test with are Bobby McFerrin, Keb'Mo, and perhaps someone on the female side, someone like Mariza. The speakers have to ace each and every one of these discs or they would fall from contention. No mercy.
As for what I have used in the past, I can recommend the following discs:
Ry Cooder's A Meeting By the River (lots of delicate tones, transients, and ambient noise); the above-mentioned RR discs of Eiji Inoue and the Minnesota Orchestra (Aaron Copland works, or Pictures at an Exhibition); a copy of Chopin Preludes (either Yevgeny Kissin or Maurizio Pollini); the Zubin Mehta recording (LA) of Holst's Planets or something similarly 'loaded' (instrument separation, clarity, ability to tame 'Saturn', and other dense passages without giving up the delicacy which is really there in good dense music); I also take along piano music which is more melodic (any number of things), I take along horn music which shimmers when done right (and for the last several years, that has been the 'French Music for Trumpet and Organ' by Hardenberger & Preston disc from bis), and I take along music with closely-miked stringed instruments (for me, the best way to get a grip on tone, and the speaker's ability to deal with all the ambient aspects (lots of stuff going on with this, just like there is with Chopin preludes). I also take along vocals, which is more difficult to deal with because I don't find female vocals the best way to test - for me, the interesting vocalists to test with are Bobby McFerrin, Keb'Mo, and perhaps someone on the female side, someone like Mariza. The speakers have to ace each and every one of these discs or they would fall from contention. No mercy.