What is a musical performance?
Now there's a deep question. Recently I thought of a novel answer.
Start with what isn't a musical performance.
Most of us have encountered those robot voices on the phone. Especially when they are reading us a phone number. Funny how hard it is to comprehend that string of numbers when there is no inflection.
Imagine one of those voices reading a novel. [Read the following in a monotone:]
"It was the best of times, it was the worst of times."
Actually, the computers are getting better at inflection and, frankly, this makes me uncomfortable. I don't want to see a machine win a vocal Turing test.
For example, paste that above text into this website. Inflection yes, but a dramatic reading...well no Oscars yet (and hopefully not ever).
Of course, now we can now make our own animated movies like this one about a misguided trombone audition. At least there's a little inflection here...the robot voices almost make it funnier.
OK, I'm getting off my point, which is this: it is clear that an UNMUSICAL performance is one lacking in variety/inflection.
Therefore, using the counter-example, couldn't we say that a musical performance is one with variety?
Not a spastic bombardment of variety unless that's what the composer wants..you never know these days. But rather variety of dynamics, speed, articulation, tone color in a way that makes sense.
So maybe I can cobble together a definition ...
Musical (adj.): Having sensible variety.
Yes, I know musicality can't really be defined. But, when I say to a student, "How can you play that with more variety?" as opposed to , "How can you play that more musically?" it sometimes gets them thinking in a more creative and positive way.