At a pivotal point in

The Medium

, the title character casts her eye on the piteous deaf-mute Toby, and sings to him, "Come, come nearer."

And then, "This way."

On paper it's nothing remarkable. But that last line, sung with just the right glint of menace, becomes the awful first lurch toward the six-body pileup to come. It also signals, when done as well as it was Wednesday night, a level of dramatic and vocal command so high you forget the talent is of the student variety.

The passage was sung by Marquita Raley as Madame Flora in the Curtis Opera Theatre production of Gian Carlo Menotti's small masterpiece, and it wasn't the only moment of surprising interpretive sophistication. Raley, 26, a master's student from Washington, D.C, is a mezzo, but the term only begins to suggest everything she can do with her voice. She has a creamy, even range, pure on top and with a powerful cutting edge below. She dips in and out of a chesty speaking voice easily. One can only marvel at the way she taps deep into pain at her young age.

Opera at Curtis exists foremost as training, but when it falls into place, it's also a potent audience experience. To reach the studio's black box upstairs in Curtis' main building you pass violin concertos emanating from practice rooms. Limited seating makes for an unusually visceral encounter.

The Medium - fully staged and, due to illness, performed with one pianist, Danielle Orlando, not two - worked because smart direction and strong voices joined in one of the repertoire's great pieces of perfection. Debussy's Pelléas et Mélisande is perfection of another kind, though it arrived in a weakened state Thursday night in the Peter Brook/Marius Constant distillation of the work, Impressions of Pelléas.

When students fall short, the less said the better, but the bigger part of the problem was a production whose costumes and makeup aimed strangely at Star Trek and, stranger still, missed. An orchestral score reduced to two pianos provided structure, but not much else.

The production concept in The Medium (both operas were set by K. Elizabeth Stevens) was traditional: the Victorian parlor where Madame Flora holds seances for grieving parents. What made the performance soar was a strong sextet of players. Toby (bass-baritone Thomas Shivone) was given dimensions beyond the anachronistic role of pathetic deaf-mute, shading facial expressions with evidence of complex thought, maintaining a body presence so cowed it seemed to take up only half its actual space. Soprano Rinnat Moriah, with nimble voice and quick vibrato, was a light-filled Monica.

The productions had telling aftershocks. Pelléas left me hungry for the real thing; The Medium made me want to go home and peek under the covers to make sure the children were all right. I did.

Contact music critic Peter Dobrin at 215-854-5611 or pdobrin@phillynews.com.

"Impressions of Pelléas" tonight at 7:30, tomorrow at 6, at Curtis, 18th and Locust Streets. "The Medium" tomorrow at 2:30 Tickets: $22. Information: 215-893-7902 or www.curtis.edu.