It wasn't about technique, though that's firmly in place. His was a real interpretation, with shape and purpose, minute manipulation of pitch and time, and fine gradations of bow speed. And then there was the sound. Armstrong - from Sonoma, Calif. - used a Guadagnini willed to the school by pedagogue Veda Reynolds. It was no doubt partly responsible for the throaty low register, responsiveness, and penetrating-but-sweet upper notes. But in Armstrong, it had a natural partner able to make it ring.
When one player sets this kind of standard, it throws down the gauntlet for the rest. Of particular pleasure were a buoyant clarinet solo and a warmly reassuring timpanist. The horns - well, for them it was a growth experience. Prieto sped through the opening heroism; he resisted making mountains out of molehills emotionally. Sentiment was present, but only sometimes, which made it all the more meaningful when he did stretch a moment or build to a climax.
The actor John de Lancie - more specifically, his dignified baritone - was brought in to the school once headed by his father to narrate Britten's Young Person's Guide to the Orchestra. Curtis' orchestra changes every season, of course, and as a guide to the present ensemble Britten's score let us know that piccolo player Niles Watson, clarinetist Stanislav Chernyshev, and harpist Anna Odell are operating on the highest level.
Conducting student Kensho Watanabe opened the program with Tchaikovsky's Romeo and Juliet - not the familiar overture but a duet for soprano, tenor, and orchestra in a reconstruction by Sergei Taneyev made from the composer's incipient materials for an intended opera. Much of the overture finds its way into this version, though meanings only suspected in the orchestra-alone version can now be confirmed in a text that speaks of nights of bliss. Sarah Shafer and Christopher Tiesi clung to each other, vocally, beautifully.
Prieto, music director of the Orquesta Sinfónica Nacional de Mexico and collaborator of Curtis director Roberto Díaz elsewhere, offered a neglected masterpiece as an encore: Silvestre Revueltas' Sensemayá (1938). Students did a respectable job with the piece, which, superficially, shares a harmonic spirit with The Rite of Spring. With a little more confidence, it could become a calling card for youth unhinged in the best possible sense, like the orchestra itself.
Contact Peter Dobrin at email@example.com or 215-854-5611. Read his blog at www.philly.com/artswatch.