The Wolf Trap Opera Company, in full motion over the weekend, offered a staged production of Mozart's "Idomeneo" (which opened Friday), and a joyous quartet of young singers in recital (Saturday), both held in the acoustically unfettered, voice-friendly Barns.

Fresh, healthy, talented and attractive. These are the attributes shared by the young singers resident this summer at the Wolf Trap company, and these added up to an ebullient "Idomeneo." Mozart's straightforward mythological tale--a plea to the gods gone horribly wrong--received straightforward direction from Joshua Major, and an airy, Italian modernist set by Vincent Mountain. Only Judith Dolan's mix-and-match costumes stirred confusion. (Were those really Puritan housewives standing beside the Hebrew slaves and Roman centurions in the Act 1 chorus?) But never mind: The focus was on singing.

In the aria "Fuor del mar," Justin Vickers got inside the title role--both vocally and theatrically--and portrayed the despair of a king who must sacrifice his son. Cynthia Watters was a radiant Ilia, vocally fetching, pure in spirit, careful in phrasing. Alexandra Deshorties sang an Elettra forceful in delivery and personality, and Nathan Granner was stalwart as the king's confidant.

Only Idamante, a pants part sung by mezzo Elizabeth Shammash, sounded pinched, unsteady. Smarter casting would have placed a romantic lead of more convincing stature in this role, especially since this prince is pursued by two statuesque sopranos.

For better or worse, the Barns' acoustics lay bare the human voice, though the orchestra in the pit (conducted by Antony Walker) projected a muffled, inside-a-milk-carton sound, often only loosly coordinated.

No such problems of accompaniment marred Saturday's recital, titled "Art Song on the Beach," an evening with a watery theme. In his introductory comments, pianist Steven Blier noted that water tends to reveal the true state of the soul. He explored the topic from several angles, with four immensely likable, well-rehearsed singers. And like the cast of "Idomeneo," they were all in the 1999 Filene Young Artists program.

Soprano Jennifer Welch used the bright, pretty, girlish quality of her voice in "Ya Salio de la Mer la Galanta," a Sephardic folk song, with intoxicating results. The rich, enfolding color of Stephanie Novacek's mezzo-soprano and her poised, expressive skills took Schubert's "Der Zwerg" properly into the realm of horror. Although her voice isn't large, she has the vocal huskiness, sexiness and emotional toughness needed to sing an alluring Carmen. In the duets for soprano and mezzo, I had great shivers of pleasure: Welch's and Novacek's voices, individually so different, blended with otherworldly beauty. Bass-baritone John Marcus Bindel had a firm, slightly sobbing quality of tone that extended down to a cavernous lower range--ideal for Rachmaninoff's "Astrovok." And Chad Shelton's ringing, large tenor and hearty turns of phrase projected a wide swath in Anckermann's "Flor de Yumuri."

Pianist Blier, who also organizes these Wolf Trap recitals, has a genius for crafting three-dimensional images within his accompaniments, sticking to his singer's text with uncanny sensitivity. Last year, in these pages, I called Blier one of the best American pianists, and nothing I heard here alters that impression.

The final performance of "Idomeneo" will be tomorrow at 8 p.m., and Blier returns July 30 with another group of singers for a program called "The History of Love in 20th Century America."

CAPTION: Justin Vickers, bringing a regal bearing to the title character in "Idomeneo."