Technique....

[Paul Whybrow]

Technique alone is never enough. You have to have passion. Technique alone is just an embroidered potholder.'

Raymond Chandler

 

[MattScho]

A dear friend of mine was the star of a good university jazz program, so when they brought in a guy (Sanborn, I think, but if not one like him) to spend a semester in residence with the program, he was paired with the guy. They worked together for three months, after which my friend expressed his dream, or making it in NY. The response "Technically, you're almost perfect. but you've got no sound." He hated the guy, but the assessment was dead on, and he never did break into music (until he swapped sax for voice and spent several years with the Met's company).
We'd call it voice.
It's both almost undefineable and make or break

 

[E G Logan]

"Technically, you're almost perfect. but you've got no sound."

Like saying, your writing is great but you've got nothing to say. Must have been a pretty hard rejection to take.