Winner of the 2014 Global Music Awards Silver Medal for her album Grieg & Prokofiev*, Helen Z. Altenbach has been a member of the LA Opera Orchestra since 2010. She is also a tenured member of the Hollywood Bowl Orchestra, the New West Symphony Orchestra, and the Long Beach Symphony Orchestra.

Born as Xiaodan Zheng to a musical family in China, she is one of seven professional cellists on her paternal side. She studied cello and piano in Russia between the ages of 9-14 and immigrated to New York City with her family in 1998. Xiaodan is a graduate of The Juilliard School Pre-College Division. She holds a Bachelor of Music degree from USC's Thornton School of Music. During her training, Xiaodan attended the Itzhak Perlman Music Program, Tanglewood Music Center, Verbier Music Festival, Pacific Music Festival, and the Perlman Chamber Music Program. Her primary cello teachers were Ron Leonard, André Emelianoff, Alexei Seleznev, and her father-James Zheng.

Xiaodan's awards include the Juilliard Honor Strings Competition, Juilliard Concerto Competition, the ASCAP Foundation Ira Gershwin award, Lincoln Center Chamber Music Society Young Artists Award, first prize Great Neck Young Artist Award in both Solo and Chamber Music categories, and second prize at Corpus Christi Young Artists Competition. She was a recipient of a fine cello on loan from the Colburn Foundation and a scholarship recipient of the Richard and Mika Hadar Foundation.

Helen won the audition with the LA Opera in 2010 while serving as tenured Principal Cellist of the Tucson Symphony Orchestra. She is currently an active freelance musician for the television and motion pictures industry in Los Angeles. She established her stage name as "Helen Z. Altenbach" in 2016 due to frequent mispronunciation of her birth name. She lives in Los Angeles with her Swiss-born husband and shelter-rescued cats.

* credited as Xiao-Dan Zheng, with pianist Clara Yang. Released by Albany Records