TONE

For piano this one is one of the best to test piano tone playing...
And anyway also one of the best interpretation of Chopin Nocturnes by Hans Moravec...

(beware : the youtube file so good it is does not replace the original recording)

Piano is the only instrument on par with voices to test the rendering of an audio system...

Any amplified music is useless for that....Anyway with a great audio system able to communicate all " hues" of sound color,  some amplified instruments or electronic music  often  seems more a seasoning than a real meal....


https://www.youtube.com/watch?v=kHXxWfSAxik

Another great thing to record is the human voice. We are all very familiar with that sound, and any "vowel" coloration (as J. Gordon Holt put it) will be glaringly obvious. WARNING: Most loudspeakers fail this demanding test. The QUAD ESL (introduced in 1957!) excelled in reproducing singing voices, setting a standard few other speakers to this day can match.

You are right for what you say about this Quad speakers...

But i will add something: all other speakers need more help from tuning room acoustic controls and they could reach some new level.... For sure each type of speakers are different, but no speakers are perfect on ALL acoustic factors even Quad...

We never listen to speakers, we listen to acoustically controlled or uncontrolled room/speakers....

But some speakers speak to us better than others in the same room....but adapt the acoustical settings of the room for each type speaker in particular and even our taste could change or be less affirmative...

No speakers beat the room says a great acoustician....

But i will repeat what you just said: QUAD is one of the greatest speaker ever designed...Precisely for the reason you said already....

@mahgister,
+1 , very good call on Moravec’s Chopin Nocturne . I’ve owned that CD for years and very close to what I hear during live piano recitals at a Steinway Piano Gallery near my home.

For those who enjoy jazz, 1. Tardo Hammer" pianist CD , "Look,Stop and Listen".studio.
2. Kenny Barren "Live At Bradley’s".
Very good CD capturing of live piano sound.
Charles

IVAN Moravec, not Hans, the robotics dude.....but thanks

For luth sound recording this one is very good...


https://www.youtube.com/watch?v=IKuEBKPxvh0

or this one:

https://www.youtube.com/watch?v=SEaqP2SceWc