Her top notes were radiant; coloratura passages were blended gracefully into Bellini's long-spun lyrical lines.
But here and there - in high coloratura passages, in midrange sustained singing - her voice turned harsh and edgy.
All parties were vague and harried in the face of Handel's coloratura passages.
She specialized in roles requiring a large sound, beauty of tone, excellent breath support, and the ability to execute difficult coloratura passages.
Miss Gruberova is not one of those, though her agile soprano did soar brilliantly in the coloratura passages of "Sempre libera."
While he could easily assail heavy dramatic roles, he was also capable of executing difficult coloratura passages and performing more lyrical parts.
But her singing was richly expressive and, in the coloratura passages, surprisingly agile.
Her voice is strong, agile and pure, with a minimum of vibrato and an exotic, emotive quality that is almost chantlike, even in coloratura passages.
Her coloratura passages occasionally lack the thrill that comes with absolute precision, and even her French diction leaves something to be desired.
The former quality equipped her to take on the very difficult coloratura passages that Mozart wrote into the Queen of the Night's part.