I am currently sequencing Beethoven's Piano Sonata No. 8 (Pathetique), and before proceeding, I did a sound library comparison on this piece as well. In the Aria of the Goldberg Variations, it was in the order of Pianoteq8>Ivory3>Synchron D-274. As expected from Pianoteq, which generates sound through real-time computation on a PC, the spectral analysis visually confirmed that the decay of the fundamental and overtones remained well-balanced and harmonized without significant irregularities. However, when I listened to Pathétique under the same conditions, I found that the order was surprisingly Ivory 3 > Synchron D-274 > Pianoteq 8.
At the beginning of the first movement, there are three striking chords marked "fp" in the first three measures, and I could immediately tell the difference here. Even when listening to the piece as a whole, the depth of sound is quite different. I wonder why. Perhaps adjusting some settings would change the outcome, but I haven’t looked into it that far.
It seems that the sound quality of the Pinoteq is suitable for polyphony, in which each note is heard and harmonized. At the same time, Ivory3 is suitable for piano sonatas, in which many notes are layered on top of each other.