Modern pianos are pretty marvelous things. Think about just the tension the huge number of strings applies to the chassis. Then the force a hand is capable of delivering to the keys, with their delicate linkages connecting them to the hammers. Then think about 19th century furniture-making techniques.
String tension across the frame of a grand piano is around 17 tons. If a frame cracked and imploded it would probably kill someone. The modern piano sound is a direct result of that metal frame combined with three string courses for most of the range.
Piano design didn't really mature until around 1850. So a lot of the most famous classical piano music was composed on not-quite-there yet prototype instruments with a thinner and less powerful sound, and sometimes also a less sensitive action.
My gf had to play a vintage antique fortepiano in a production last year, and the solo sound is closer to a fat harpsichord with better dynamics and slightly random tuning than a modern piano.
It's what Mozart, Beethoven and Haydn would have played: they literally never heard their music on a modern instrument.
> Piano design didn't really mature until around 1850. So a lot of the most famous classical piano music was composed on not-quite-there yet prototype instruments with a thinner and less powerful sound, and sometimes also a less sensitive action.
This is really apparent in the first movement of Beethoven's Moonlight Sonata. In the original instructions, the pedal was to be held throughout the entire piece. On a piano of Beethoven's time, that would lead each chord to blend into the next without overpowering it. But if you try to do that on a modern piano, the tones are sustained for so long that all the chords get muddled together and the result is a mess.
