Who are we?
Polyphonix is a professional vocal ensemble based in Simi Valley, directed by Bonnie Graeve. The group performs a diverse repertoire of classical, jazz, and popular music, delighting audiences with polished harmonies and skillful artistry.
Our Mission
Our mission is simple yet profound: "To create artistic performances while giving back to our community." As a volunteer organization, profits from our performances are donated to the Simi Valley community through contributions to local organizations, individuals, and community projects. We believe in using our art to strengthen the bonds of community and inspire joy through music.
Meet Our Singers
Brianne is a classically trained musician and dedicated educator who earned her Bachelor’s, Master’s and teaching credential from CSU Northridge. She has taught for 26 years in Los Angeles and Ventura Counties and spent six memorable years hosting the High School Oratorio Project with the Los Angeles Master Chorale at Van Nuys High School. As a performer, Brianne has appeared with artists such as Barbara Streisand, Barry Manilow, and Dianne Reeves and has sung with the Los Angeles Master Chorale, The LA Philharmonic and the Hollywood Bowl Orchestra. She was also a part of the award-winning Northridge Singers who earned the title Eisteddfod Choir of the World in 2003. She is honored to sing with Polyphonix and share her passion and experience with this commendable ensemble.
Brianne Arevalo
Debra has always loved singing, being in choirs in elementary, middle school and High school. She earned her Bachelor Degree at Pepperdine University, majoring in Marine Biology, but still joined every choir and sang in the operas. After college, she continued her love of music by serving on church worship teams and community choirs including the Moorpark Masterworks Choral. She especially loves choral singing, since everyone has a part and together they contribute to a wonderful whole. What she loves the most, is the moment when the harmonies gel and the sound is heavenly. Debra taught sciences for 42 years, mostly in Simi Valley. Now retired, she has more time for music! It is her joy and privilege to be a member of Polyphonix.
Debra Bickford
An Iowa native, John began his musical journey with the violin at the age of nine. His commitment to music was demonstrated by his consistent participation in Orchestras and Choirs from elementary school through high school, culminating in his selection as a member of both the prestigious Iowa Allstate Choir and the Iowa Allstate Orchestra. His dedication earned a music scholarship to Pepperdine University, where he went on to graduate with a degree in Music Education. After graduating, he moved to Simi Valley where he taught middle school science for 35 years before retiring. During that entire time he has continued to share his passion by working in various orchestras and choirs throughout the Simi Valley and Moorpark area.
John Bickford
Peter Davis
Peter Davis is a vocalist and classically trained guitarist, currently working as the Vocal Music Director at Royal High School. A New England native, Peter attended the Hartt School of Music in Hartford Connecticut, where he studied both Music Education and Guitar Performance. He has performed extensively as a both vocalist and guitarist throughout the greater Boston area, and frequents many open mic nights in and around Simi Valley since moving to California. In addition to his experience as a classical musician, Peter has also worked diligently to organize and perform weekends of worship music workshops and performances across North America, in cities such as Boston, Cleveland, Portland, and Los Angeles. When he’s not teaching or performing, Peter loves to play board games, go on road trips, and cook gourmet meals.
Christi Ebenhoch
Born and raised in Southern California in a musical family, Christi has built an exceptional career as one of the top female session singers, vocal contractors, and live background vocalists in the industry. Christi’s vocals can be heard across television commercials, radio ads, film scores, and hit TV shows. As a vocal contractor, she specializes in finding top-tier talent for studio sessions, background vocals, and live events. Her television and film credits include vocal work and contracting for major productions such as The Voice, America’s Got Talent, American Idol, and Crazy Rich Asians. She has also contributed vocals to national campaigns for brands like Ford, Survivor, Carl's Jr., and Mercedes-Benz. On stage, Christi has toured nationally with artists such as Oingo Boingo, John Tesh, and Bobby Caldwell. Her studio and live collaborations span top-tier clients including Disney, Fox, Paramount Studios, Nickelodeon, the Backstreet Boys, Weezer, and more. Christi currently resides in Los Angeles with her husband and two children.
Jenny Fuller, Treasurer
Jenny earned her Bachelor’s Degree from Pepperdine University in Business Administration and her teaching credential from CSU Northridge. She retired from the SVUSD after teaching 5th grade for over 20 years at Hollow Hills Elementary and leading their choral music since 1992. During that time, her choruses and classes performed in multiple musical productions, and for the local Lew Roth Awards, the Ronald Reagan Library, SV Read Across America and Arbor Day celebrations, and the New West Symphony. With retirement has come a renewing of her interest in playing the violin, joining the Simi Valley Community Orchestra during its inaugural year, as well as the Simi Valley Chamber Orchestra and Simi Valley Symphony Orchestra. She also volunteers for other nonprofit organizations, and enjoys hiking, traveling, pickleball, and mostly spending time with her children and grandchildren. Music has played a defining role in her life, and she hopes to continue to bring the joy of music to the community through involvement in Polyphonix.
Bonnie Graeve, Director
Bonnie was born and raised in SD where she began studying piano, singing and saxophone. She went on to earn her Bachelor of Music Education degree in Instrumental/Vocal music and a MA in Educational Administration. Throughout her career, Bonnie has taught in SD, CO and CA. Her experience includes directing K-12 instrumental and vocal music, Community College and Church Choirs and teaching private lessons. Under her leadership, Bonnie’s choirs have earned numerous awards and had the honor of performing multiple times at Carnegie Hall, Kennedy Center, Orchestral Hall and Disney Hall. She has been recognized as Educator of the Year with both the Lew Roth Award and Spotlight Award in Simi Valley. Since her retirement from SVUSD at Royal High School, Bonnie enjoys volunteering for several local organizations and teaching in her home studio. Rehearsing and performing with the talented musicians of Polyphonix continues to be a rewarding and inspiring part of her musical life.
Matt Harmon is a vocalist from Simi Valley and a graduate of Royal High School, where he performed in Concert Choir, Chamber Singers, and Jazz Choir under the direction of Bonnie Graeve. During his time there, he participated in the prestigious Idyllwild Arts Camp and had the opportunity to perform at the Dorothy Chandler Pavilion under conductor Grant Gershon. Music has been a lifelong influence for Matt, shaped in part by his father’s involvement with the Masters of Harmony and several barbershop quartets. He has also sung in church from a young age, and has contributed to multiple competition wins and earned recognition for Best Jazz Soloist. Outside of music, Matt enjoys camping, traveling, restoring classic cars, attending car shows, and going to Dodger games. He values the sense of community and shared purpose that comes from making music with others and is grateful for every opportunity to continue growing as a singer.
Matt Harmon
Mike Pulsipher
Maggie Robertson, Assistant to the Director
Maggie Robertson is a distinguished jazz vocalist from Simi Valley, CA. She holds a degree from CSU Long Beach’s Bob Cole Conservatory of Music, where she completed the Jazz Studies program. At CSULB, Maggie sang in their premier vocal jazz ensemble, Pacific Standard Time, for three years, and was in the Bob Cole Chamber Choir for one year. Before Long Beach, Maggie earned her AA in music from MiraCosta College in Oceanside, CA. There, she sang in the Frequency vocal jazz ensemble and had the honor of directing her own vocal jazz quartet, Q#. This ensemble performed complex music and engaged in recording sessions, fostering her leadership and collaborative abilities. She has received multiple Downbeat awards for her excellence as both an outstanding soloist and ensemble member.
Karthik Srivatsan first took up music at the age of six, when his parents enrolled him in a piano class in his school of Sunnyvale, CA. In eighth grade, he joined his middle school choir, and continued through his four years of high school, auditioning for-- and making it into-- the regional Honor Choir three times, and All-State twice. When he went to college at the University of Michigan, he joined the Men’s Glee Club under the direction of Eugene Rogers in his freshman year, and was a part of it for five semesters. At the end of 2024, he joined the Simi Valley Community Choir, and is now singing in Polyphonix. Outside of music, Karthik has bachelor’s and master’s degrees in aerospace engineering. He also is an avid runner, likes to travel, and dabbles in photography.
Karthik Srivatsan
Want to join Polyphonix? See any of our members for more information! Auditions are ongoing.
Our Next Male Singer!