IMO, too much is made of the idea that piano is the most difficult instrument to record. EVERY instrument, including the human voice, has unique tonal and other characteristics that make it uniquely difficult to record/reproduce. The more familiar one is to the full range of sounds and tonal nuances that any given instrument is capable of, the more that one is able to identify tonal deviations and so we deem that instrument “the most difficult”. If one must be picked as most difficult and useful I would agree that it is the human voice.
It is true that the piano’s very wide frequency range makes it uniquely difficult to record, but the piano does not have nearly the wide variability of possible tonal colors and effects that other instruments are capable of. Even the often mentioned dynamic range of the piano is still narrower than that of other instruments. The human voice, trumpet and even the clarinet are capable of wider dynamic range than the piano. A clarinet can play much more softly than the piano and maxes out at around 114 db, while the piano’s volume maxes out at around 100 db. The human voice ups the ante by maxing out at around an astounding 125 db and is also capable of sounding in a faint whisper; all with incredibly varied possible tonal colors and textures.
For me, recorded piano is most valuable for assessing pitch stability of turntables. The decay of recorded piano notes are a great test.
