If you get a ticket to see the Le Villi/Mese Mariano opera twinbill at Sottile Theatre, you won't need to sit close to hear the singing star. Jennifer Rowley is the most powerful soprano voice to hit Spoleto Festival USA since Sondra Radvanovsky sang the title role of Verdi's Luisa Miller in 2000. Radvanovsky had the vocal artillery to overpower cavernous Gaillard Auditorium, and Rowley makes equally quick work of the Sottile with her potent larynx.

• Dinyar Vania as Roberto in Le Villi (Photo by Julia Lynn)

It jumps out at you somewhat inconveniently in Umberto Giordano's Mese Mariano (Mary's Month) because the singing until then, entrusted by conductor Maurizio Barbacini largely to children and members of the Westminster Choir, is mercilessly exposed for its lack of force as soon as Rowley arrives. Carmela's arrival is also a relief dramatically, because the opening minutes of the drama are taken up by an irrelevant visit from a condescending Contessa at the orphanage where Carmela had left her child years earlier due to the demands of a cruel husband.

Surely there are more graceful ways to introduce the nuns and the children of the orphanage, but librettist Salvatore di Giacomo, adapting his own short play, is hard-pressed to stretch out the action, which clocked in at just over 36 minutes on Memorial Day. Of course, we want to hear Rowley singing the poignant story of how she gave up her dear son, pouring out her heart and her guilt to childhood friend Suor Pazienza. But then we must submit to an exit by Carmela to pray in the chapel while the nuns bring out her son.

Now the story totally disintegrates as the nuns begin to learn - after all the children have formally appeared for the Contessa's review, mind you - that Carmela's son suddenly died the previous night! This unbelievable, unprecedented reticence among women and children is followed by a merciful cover-up as Pazienza fabricates an excuse for why Carmela cannot see her boy. Guess she misses the funeral, too.

With a bunch of adorable children coupled with Rowley's bravura, the Spoleto production actually played quite charmingly. Puccini's Le Villi is far more substantial stuff, but it suffers from an opposite kind of malady. This story, climaxing in the destruction of a faithless fiancé by the ghosts of heartbroken betrayed women, is unduly compressed. Instead of a middle act, where Roberto is undone by an evil temptress in the big city - and his jilted Anna dies of mad, broken-hearted despair - these developments are revealed to us by a narrator over the PA system, with the scant compensation of a couple of ballet interludes.

Stage director Stefano Vizioli and set designer Neil Patel further disfigure the storyline by turning Anna and her fellow Willis (those vengeful fairy ghosts who are the title characters) into inmates in an insane asylum. By transforming the dark wood where the latter-day Furies gang up on Roberto into a rubber room, Vizioli must also change the ending - and, I suspect, further shorten the score, because this Roberto isn't doing anything like dancing himself to death.

With Pierluigi Vanelli's choreography turning the Willis into catatonic zombies, the alteration is not at all ludicrous. Puccini's music, with more Wagnerian colorations than we find in his later works, takes well to the frenzy that Vanelli whips up with Rowley and ten other dancers. But the composer is already a fine tunesmith, and it was gratifying to find that Rowley was no longer blowing the other frontliners away after intermission.

Unlike Rowley, tenor Dinyar Vania doesn't have a Metropolitan Opera debut on his calendar yet, but after hearing Vania sing Roberto's rueful "Torna ai felici dì" (Return to the happy days) upon his return from the city, I wouldn't count him out for the future. There is heft and magic in the voice. Nor is power Rowley's only asset when she sings her big arias. Although her upcoming debut in Bohème is as Musetta rather than Mimi, she proves quite capable of a silken softness. With baritone Levi Hernandez rounding out the cast as Anna's father Guglielmo, we're treated to beautiful singing from beginning to end.

Toshio Hosokawa's new opera at the Dock Street Theatre, Matsukaze, is an odd mishmash derived from a very old Japanese Noh play written by Kanze Kiyotsugu Kan'ami late in the 14th Century and revised by his son Kanze Motokiyo Zeami. As you might expect, Hosokawa's music vividly evokes the Orient, but Hannah Dübgen's libretto is jarringly in German, while Chen Shi-Zheng's stage direction - suffused with spooky lighting and video effects - disdains the use of even the most basic props mentioned in the simple script.

In the original Noh play, the fisherwomen sisters Matsukaze (Pine Wind) and Murasame (Autumn Rain) wheel out a cart with pails of brine. Shi-Zheng can't be bothered, so the one lighting effect explicitly mentioned in the original script, the women poetically catching the moon in their pails, isn't even mimed. More annoying, the conventions of the Noh play immediately distinguish which sister is which by the masks they wear.

Dübgen's libretto doesn't compensate. I wearied of trying to differentiate between the two and just guessed - wrongly. If you read the thorough synopsis in the program booklet, you'll be able to make a positive ID, but only late in the opera as we reach the mad climax.

Although the music is beautiful and the Spoleto co-production with the Lincoln Center Festival is a neat 71 minutes, phrases and sentences inch toward us at a painfully glacial pace in the early going - and traditional Noh plays are replete with singing and instrumental accompaniment, so it's not like Matsukaze has been starving for Hosokawa's music over the past 600 years. Resident conductor John Kennedy is a persuasive advocate, passionately leading the Spoleto Festival Orchestra through a score that is desperately devoid of allegros, making the case that it's a fascinating mix of Western orchestral textures spiked with Eastern winds and percussion.

The ghostly brew of Chris Barreca's set design, Scott Zielinski's lighting, and Olivier Rosset's video is often mesmerizing in a compelling way from the moment a humble Monk reaches the Suma shore. There he learns from a Fisherman about the two impoverished sisters who mourn perpetually for Yukihira, the nobleman who loved them for three years, pledged to return when he was called away, and died tragically without fulfilling his pledge.

Settling in for the night at the seaside salt shed, the Monk encounters the ghosts themselves. Perhaps if the Monk were Asian, I'd have less of a problem with his singing in German, but Gary Simpson looked like a Christian monk, so I did, and the gruffness in his tone only amplified the discord I felt when attention shifted his way. Sopranos Pureum Jo as Matsukaze and Jihee Kim as Murasame were a huge relief from this discomfort. Both are lustrous individually and harmonious together. The German doesn't matter when they sing. My only remaining worry was not knowing which was which.