[music] about notes duration

Yes that's correct. What I meant was that there is no less than infinite variants in human playing that cannot be measured (or we'd take infinite time to do it).For instance, a quarter note is 1 beat, but how long does it last? if you press piano pedal it can spread several beats, and together with next notes it may form a chord. In guitar arpeggios this happens quite often, if not always...even in a melody, the duration of notes depends on the instrument and on the interpretation. If we want legato the note shall last the whole beat, or even a little longer into next note (specially for piano players).The strength applied, the direction strings are picked, the left hand and left arm movement, ... all these are affected by a trained instrumentist humour and techique, and surelly affect the way a music sounds. If you reduce this to a one-dimension machinery, it'll sound like... a machine.I don't consider that even music.