I think the low strings usually get tuned about half a semitone or more lower just to sound in tune with the rest of the instrument.
It'd be interesting to know what the railsback curve looks like for this long piano; I'd expect it to be a lot flatter.
I imagine you could also flatten out the curve on the treble end by using thinner gauge wire, but I suppose there's probably a trade-off in terms of volume or durability, otherwise all pianos would use thin wire for the treble strings. (I think most pianos use wire that's a little thinner in the treble, but not by much. I might be wrong about that, though.)
It'd be interesting to know what the railsback curve looks like for this long piano; I'd expect it to be a lot flatter.
I imagine you could also flatten out the curve on the treble end by using thinner gauge wire, but I suppose there's probably a trade-off in terms of volume or durability, otherwise all pianos would use thin wire for the treble strings. (I think most pianos use wire that's a little thinner in the treble, but not by much. I might be wrong about that, though.)
https://en.wikipedia.org/wiki/Piano_acoustics#The_Railsback_...