I think you meant second note. :)
I think you meant second note. :)
Note held too long? Tempo too slow.
Note released too early? Tempo too fast, or note erroneously played staccato.
What would be hard though is interrupting the performer during this window and stopping them prior to playing the second note.
Errata: Some first notes are longer than a quarter notes. Some tempos are different than 120 BPM. It's possible to notice something before you can effectively communicate it.
"not quite my tempo"
Also, Fletcher still takes several notes to hear the incorrect tempo.
I'm sure if you're very experienced with playing with orchestra or chamber (as Uchida and my friend are) then there is a non verbal language they dial into, call it telepathy if you will, that lets them sense that count in.
Sounds fictional but dancers and fighters will also attest to being able to read the thoughts of their partners...
So the first note may also include 1-2 bars of silent counting
Teacher: Have you ever learnt Villa-Lobos étude #1? (Reaches for his guitar)
Me: this thing? (I play one note, very possibly a semitone off as it’s a reach past 12th fret on the D string)
Teacher: (with his back to me) No, that’s #4
Me: (wtf!)
Uchida is famously fastidious. She has 5 pianos at home, no one is allowed to touch them and she allegedly knows whether someone does. If you listen to her you can hear just how fussy she is.
I went to listen to her play the Schubert Impromptu cycle at Southbank and she walked off the stage mid-piece because there was some alarm sounding outside haha.