Music review

BOSTON SYMPHONY ORCHESTRA

At Symphony Hall, Friday (repeats Saturday and on a date to be announced; program will include Ravel’s “Le Tombeau de Couperin’’). 888-266-1200, www.bso.org

“It’s casual Friday,’’ Boston Symphony Orchestra horn player Rachel Childers said, smiling at the front of the stage before the beginning of Friday’s concert. “Meaning the men get to wear all black.’’ Forget the shortened program. Forget the “casual’’ dress. (For the women of the BSO, there is no visible difference between a regular night and a casual night.) There was nothing casual about the BSO’s performance. Two musical depictions of dreams from almost 200 years apart invited the audience on an exhilarating journey.

When we dream, we do so in improbable layers, in unique labyrinths, in palimpsests of experience, memory, and wishes melded into ephemeral reality by our subconsciousness. George Benjamin’s “Dream of the Song’’ was written with countertenor Bejun Mehta’s intoxicating voice in mind.

Each brief movement bloomed like a moonflower, tactile petals of textures from Mehta, the orchestra, and the women’s vocal group Lorelei Ensemble overlapping. Texts in English and Spanish entwined, chosen not so much for their meaning as for their sound.

Where one layer began and ended was not always evident; in one moment, a pure vowel shifted from Mehta to Lorelei Ensemble with such fluidity that the distinctions between them seemed to disappear, dissolved into the fabric of the universe. The piece did not so much end as recede, as the colors of a dream do once sunlight hits the eyes, and the unshakeable feeling of having witnessed something magical lingered.

“I asked Mr. Mehta if he would elaborate as to what the ‘dream of the song’ was, and he demurred, saying it was up to you,’’ Childers explained in her pre-concert remarks.

Unlike in Benjamin’s piece, nothing is up to the listener in Berlioz’s “Symphonie fantastique.’’ Every moment’s meaning is programmed in the composer’s copious notes, which detail an opium-laced dream become nightmare of obsessive infatuation. The piece is a decadent spectacle of high melodrama, and the gargantuan orchestra was replete with thunderous percussion and flaring brass. Symphony Hall itself became an instrument, as timpani rumbled from the second balcony, offstage church bells pierced the air, and an oboe called to a plaintive English horn from the organ loft.

Andris Nelsons was in his gleeful element as he led a grand “March to the Scaffold,’’ and “Dream of a Witches’ Sabbath’’ was notably lush and legato in comparison to many other renditions, emphasizing that daydream and nightmare alike sprang from the same decadent seed.

BOSTON SYMPHONY ORCHESTRA

At Symphony Hall, Friday (repeats Saturday and on a date to be announced; program will include Ravel’s “Le Tombeau de Couperin’’). 888-266-1200, www.bso.org

Zoë Madonna can be reached at zoe.madonna@globe.com. Follow her on Twitter @knitandlisten. Madonna’s work is supported by the Rubin Institute for Music Criticism, San Francisco Conservatory of Music, and Ann and Gordon Getty Foundation.