Richard Dunn said:
A human being being technically good at his / her chosen skill is not the same thing. You cannot measure them, you have to make that judgement subjectively. Though I am sure some score shufflers and readers will dissagree.
I don't intend any disrespect here, and please don't take this the wrong way, but I'm guessing you may not be a musician

.
For a musician, the technical skill of 'playing the right notes' is related to and an important part of
but not the same as the skill of communicating with an audience. This is stereotypically a problem with intensively-trained young players who can play anything you like as fast as you like note-perfect but who lack the experience and the understanding to make it say anything interesting; conversely, the stereotypical player on the brink of retirement with a lifetime of experience may not be as sure-handed as (s)he once was, yet has the ability to bring a piece of music to life through a thorough understanding of its nuances, despite wrong notes creeping in from time to time. What we loosely call 'musicianship' depends on subtle and - importantly -
context-sensitive variations in tempo, dynamic level, tone-colour, pitch and myriad other factors. These variations will themselves change constantly throughout the performance as the context changes.
This whole "sound vs music" argument arises because of the following (erroneous) anthropomorphic train of thought: (1) musicians play music; (2) some musicians have excellent technique and poor musicianship, or vice versa; (3) hifis also play music; (4) hifis are thus a bit like musicians; (5) therefore probably some hifis also have excellent technique and poor musicianship, or vice versa. Musicianship depends on subtle, context-sensitive changes, whereas the performance of hifis is to all intents and purposes deterministic: for a given stimulus, you always get the same response. Thus for example, while I've said that variations in tone colour are one important aspect of musicianship, and incorrect tonality is certainly one thing that can go wrong with a hifi, it'll be wrong in basically the same way throughout the performance, or at least if it varies for whatever reason it'll be in a grossly simpler way than the subtle changes being made moment-to-moment by the artist in the recording
so you'll still hear the changes.
The fact remains, of course, that some people maintain that they can hear "musical differences" between two physically identical sounds - good luck to them.
