The biggest issue that I have in using piano to judge a loudspeaker is the enormous variety in tonality between different pianos. It's not just grand vs upright, but various sizes, manufacturer tonality variations, and even the age of the hammer pads. I'm never sure what the particular piano on a particular recording is supposed to sound like. Okay, really bad is really bad, but maybe that clangy sound isn't the speaker, it's just a small upright with worn hammer pads.
Even if I really know a recording and am doing a controlled A/B, it's hard for me to really feel comfortable making a judgement on a speaker's ability to "do" piano properly. Shy of that type of comparison, I find voice much more useful than piano for judging a speaker's tonal neutrality. But, that's just me and YMMV.
Marty
Even if I really know a recording and am doing a controlled A/B, it's hard for me to really feel comfortable making a judgement on a speaker's ability to "do" piano properly. Shy of that type of comparison, I find voice much more useful than piano for judging a speaker's tonal neutrality. But, that's just me and YMMV.
Marty