My Morley upright has its last damper on the D 2 octaves-and-a-bit above middle C.
The difference in the sound either side of this discontinuity is sometimes quite upsetting. Should it really be that noticeable? I can play a light staccato passage at that pitch and suddenly just one note sticks out.
My belief is that it shouldn't be noticeable and would advise asking for a diagnosis from a tuner/technician. Do you know if the discontinuity in sound coincides with part of the piano frame which perhaps separates the strings of two notes ?
Tuner came yesterday and said there was nothing unusual about it and that almost all grand pianos finish in the same place. And he said any composer worth their salt would just not write a passage which was spoilt by the sound of the discontinuity at that point - they would avoid it.
I learn something new from our tuner every single time he comes . This time I learnt that una corda does not mean that on a grand piano the action moves so that the hammer hits just one string - that apparently would be too far and ,wouldn't work well mechanically: it hits two strings, so una corda is either incorrect or probably it means "miss one string".
He was also impressed that not only did we stay in the room while he made what he admits is a horrible noise (well, my husband didn't think so, he was fascinated by the process) but that the dog stayed there too. Normally he says they will run for the hills as soon as he starts.