Composers are always limited by the instruments they write for.
Beethoven in his mature works liked to explore the full range of the piano, the last movement of the 4th piano concerto is a case in point. There is also a section in the 1st movement of the Sonata Op110 where Beethoven clearly wants to go higher than the range of his piano allowed, and as a result there is a fairly obvious ‘break’ in the way the music sounds. It is common practice these days for pianists to play what Beethoven wanted, rather than what he wrote.
At two points in his Toccata, Khachaturian runs out of notes in the upper range – at the end of the first section and right at the end. The range of the Stuart allows the player to continue the sequence right up to the top F. Once again, the result is clean, effective and very, very logical.
What this means is that the player can, with appropriate judgement, expand the music to fill the notes available. For example, doubling of octaves, both in the bass and treble, can produce effects which emphasise or develop different sounds and effects which can be in total harmony with the music and the composer’s intentions.
The extended range of the piano expands the musical possibilities. I use the extra notes, both bass and treble, quite often these days, and I do not believe that I am in any way detracting from the music. I am reinterpreting and expanding the music.
For a serious musician, this is an ideal position to be in.
How far can you go, I wonder?