"It's a very unusual thing to open your mouth to sing a note and it feels like all four notes of a chord are coming out of your mouth," he said. "We all have the feeling of being connected to each other." A quartet was born.
Ask most people to picture a jazz quartet, and they'll probably summon up a horn, a piano, a bass and a drum set. Maybe, if they're feeling inventive, a Hammond organ in place of the piano. Vertical Voices occupies the uncommon corner of the music universe known as ensemble vocal jazz.
Rather than singing in a more familiar swing or Big Band style, these vocalists use their voices as free-form instruments, playing with wordless sounds, unusual harmonies and tonal color. It's a new generation of scatting.
The quartet is composed of Marsh and his soprano wife, Julia Dollison, with alto Jennifer Barnes and bass Greg Jasperse. A rhythm section of piano, drums and bass often backs up the foursome, with a cappella and improvisation mixed in.
It's a fresh sound from a fresh ensemble. The quartet performed its first gig at the end of 2010. This summer, it's playing the Stanford Jazz Festival for the first time. At the festival, which opens tonight and runs through Aug. 4, Dollison will serve on the faculty and Vertical Voices will perform on July 19.
"It's a big honor," Marsh said. "We expect a really nice and educated crowd."
Marsh also expects a musically sophisticated crowd that will appreciate Vertical Voices' style, which isn't always radio-friendly.
As an example, Marsh cites the ensemble's arrangement of the Maria Schneider ballad "Sky Blue." The vocalists sing lush, clustery harmony high in their ranges, often in falsetto, with the rhythm section playing underneath. Through the mingling of wordless sounds, Dollison's voice "floats along like a soprano saxophone," her husband said fondly.
Schneider, a genre-bending American composer with a 17-member collective orchestra, was the original inspiration for the quartet. In 2010, Dollison and Marsh released the album "Vertical Voices: The Music of Maria Schneider," using only their multi-tracked voices paired with Schneider's rhythm section.
When the pair wanted to perform this music live, they needed two other voices, and asked Barnes and Jasperse to join them. Now the singers also perform new music; all four compose and arrange; and they're working on their first album together.
A handful of videos on Vertical Voices' website give a preview of the album, with the four singers performing the dreamy Pat Metheny number "Travels" (with words by Dollison) and the wordless, energetic "The Cry and the Smile," composed by Nando Lauria.
The Vertical Voices members are also inspired by the veteran American vocal group The Manhattan Transfer and are big fans of the New York Voices ensemble.
Assembling their multi-layered music has an added challenge: It's generally done long-distance. Marsh and Dollison live near Sacramento, Jasperse is based in Los Angeles, and Barnes is the director of vocal jazz studies at the University of North Texas.
The four also have a myriad of other music obligations. Marsh auditions choir singers to perform with Ben Folds' symphony-orchestra shows; Dollison teaches at Berkeley's Jazzschool Institute; and Jasperse's teaching locales include the New York Voices Vocal Jazz Camp at Bowling Green State University.
So the quartet doesn't rehearse together much. With too many lags on Skype to allow remote rehearsals, the singers learn their parts on their own.
"Largely everything materializes on stage," Marsh said.
Plenty of other new sounds will be materializing this summer at Stanford Jazz. Now in its 40th season, the festival begins tonight in Dinkelspiel Auditorium with the Panamanian pianist Danilo Perez.
Besides the members of Vertical Voices, other young performers include singers Sasha Dobson and Gretchen Parlato on Aug. 1, and Menlo Park native and pianist Taylor Eigsti on July 30. Festival founder and director Jim Nadel will lead his annual "Early Bird Jazz for Kids" program to attract an even younger generation, on June 23.
The festival lineup also includes performances by venerable drummer Roy Haynes; trumpeter Ray Brown, a former member of Stan Kenton's band; bebop saxophonist Charles McPherson; Julian Lage, Victor Lin and Jorge Roeder playing "Hot Club" acoustic jazz on fiddle, guitar and bass; and singer Luciana Souza performing Brazilian jazz with guitarist Romero Lubambo.
What: The concerts and lectures of the Stanford Jazz Festival, running concurrently with jazz camp and adult jazz residencies for students
Where: Stanford University, with venues including Dinkelspiel Auditorium and Campbell Recital Hall. (Vertical Voices performs at 7:30 p.m. July 19 in Dinkelspiel.)
When: Concerts run June 22 through Aug. 4, mostly in the evenings.
Cost: Ticket prices vary, with discounts available for students, children and groups.
Info: Go to http://www.stanfordjazz.org or call 650-725-ARTS.