Repertoire & Resources Chairs
Emily Cothern
Biography
Emily Cothern, graduate of Millikin University, will be starting her fourth year of teaching in Jackson, MO. She taught Kindergarten through 4th grade for the past three years and is starting her fourth year of teaching at the 5th and 6th grade building! Emily has a long history with the American Choral Directors Association, participating in district, state, and national honor choirs. She is a legacy member of MCDA with her parents, grandparents, and aunts serving the organization. Emily loves to bake and enjoys time spent with her husband, Isaac, and her sweet puppy, Connie.
Karen Kenaston-French
Biography
Karen Kenaston-French is Professor and Director of Choral Activities at the University of Texas Arlington (UTA), where she conducts the A Cappella Choir, teaches graduate and undergraduate conducting, and leads the Vocal Area. Under her leadership, the UTA A Cappella Choir has performed at prominent conferences, including the National Collegiate Choral Organization (2019), Southwestern Division American Choral Directors Association (2022 and 2016), Texas Music Educators Association state convention (2024, 2019, and 2014), and national ACDA conventions (2025 and 2015). She has prepared the choir for regional collaborations with esteemed ensembles such as the Dallas Symphony Orchestra, Fort Worth Symphony Orchestra, Dallas Winds, Texas Ballet Theatre, and Fort Worth Chorale, as well as for the Rolling Stones and The Eagles. Additionally, the A Cappella Choir was recognized as a finalist for the American Prize for Choral Performance in 2021 and 2014.
In 2019, Dr. Kenaston-French became the Artistic Director and Conductor of the Fort Worth Chorale, making her the fifth conductor in the organization’s 57-year history.
Before joining UTA, Dr. Kenaston-French was the Director of Choral Activities at Austin Peay State University in Clarksville, Tennessee, where her Chamber Singers performed twice at the Tennessee Music Education Association state conference and participated in master classes with Chanticleer, Cantus, and Libby Larsen. She has also taught conducting at Southern Methodist University (SMU) and the University of North Texas (UNT) and served as director of music ministries at Plymouth Park United Methodist Church in Irving, Texas, from 1986 to 1998. As a sought-after guest conductor, she has led honor choirs across the U.S., the Texas two-year college All-State choir, and numerous TMEA region choirs. An active lecturer and adjudicator, she has presented on topics such as choral tone, conducting, rehearsal techniques, and performance practice for organizations including SMU, Choristers Guild, Texas Choral Directors Association, and various universities, school districts, and churches.
A native of Huntington, West Virginia, Dr. Kenaston-French holds a B.A. in vocal performance from West Virginia Wesleyan College, dual M.M. and M.S.M. degrees in choral conducting from SMU, and a D.M.A. in choral conducting from UNT. While at UNT, she was recognized as the Outstanding Graduate Student in Conducting and Ensembles and received the Pi Kappa Lambda Outstanding Doctoral Student Award. Her conducting mentors include Jerry McCoy, Mel Ivey, Lloyd Pfautsch, Jane Marshall, and Larry Parsons. In 2011, she participated in the Choral/Orchestral Master Class at the Oregon Bach Festival under Helmut Rilling and Jeffrey Kahane. Her vocal studies include graduate work with Lynn Eustis (UNT) and Linda Baer (SMU).
Dr. Kenaston-French has contributed scholarly work, including her article “The Teachings of Jean‐Antoine Bérard,” published in the Journal of Singing (November 2009). She was a member of the Dallas Symphony Chorus from 1993 to 2003 and was part of the inaugural Robert Shaw Festival Chorus at Carnegie Hall in 1991.
Nathan Wubbena
Biography
Nathan Wubbena is known for his “innate ability to communicate, lead, and inspire students and adults alike.” He currently serves as Artistic Director of both the Boulder Children’s Chorale and Longmont Chorale, and is the founder of Ascent Vocals. Ensembles under his leadership consistently earn high praise and frequently collaborate with professional groups throughout the region. He is also in demand as a guest clinician and honor choir conductor across Colorado, directing elementary through high school ensembles as well as his fellow directors.
Nathan holds a Master of Music in Music Education with a Conducting Specialization from CSU, as well as a Bachelor of Music Education from UNC. He is the Community Repertoire & Resources chair for the Southwestern region of the American Choral Directors Association. In 2015, he received the Outstanding Young Music Educator Award from the Colorado Music Educators Association, honoring outstanding achievement in educators with up to five years of experience. He also helped found the Colorado Middle All-State Choir and served as Co-Chair of its governing board.
Nathan firmly believes music is for everyone. Whether working with professional colleagues, young singers just finding their voice, or community members raising their voices together, he strives to create spaces where music and collaboration bring beauty and joy to performers and listeners alike. “Beyond his musical and professional achievements, Nathan Wubbena is a person of exceptional integrity, honorable character, and genuine kindness. He is a leader who makes a lasting impact on his students, his community and beyond.” Nathan lives in Longmont with his wife and two children, where he enjoys cheering for the Broncos, exploring the outdoors, and spending time with his family and dogs.
Karl Nelson
Biography
Dr. Karl Nelson has served as the Director of Choral Studies at the University of Central Oklahoma since August of 2006, where he oversees the choral program, directs the Concert Chorale, Second Street Singers (vocal jazz), and teaches undergraduate and graduate conducting. A student of Kenneth Fulton, Michael Butterman, Jindong Cai, Chester Alwes and Joe Grant, he earned a Doctorate of Musical Arts and a Master of Music in Choral Conducting from Louisiana State University and a Bachelor of Science in Music Education from the University of Illinois at Urbana-Champaign. Under the direction of Dr. Nelson, the University of Central Oklahoma Concert Chorale has performed at the Oklahoma Music Educators (OkMEA) Conference and College Music Society National conference. The UCO Concert Chorale regularly tours throughout the state of Oklahoma and internationally, recently performing in England and Scotland in 2023, participating in the Brandenburg Choral Festival in London. The Second Street Singers recently performed for the 2025 OkMEA Conference. He has served as clinician and adjudicator on numerous occasions, working at the grade school, high school, college, sacred and community settings. Dr. Nelson has served as professor at Guizhou Normal University in Guiyang, China for choral conducting students in the summers of 2024 and 2025. He was selected as one of fourteen emergent choral directors from the United States to participate as a conducting fellow for the 2015 International Conducting Exchange Program in Sweden, sponsored by the American Choral Directors Association (ACDA). As a member of ACDA, Dr. Nelson serves as the Southwest Division Repertoire and Resource (R&R) Chair for Vocal Jazz. He has previously served as the SWACDA R&R Community Choirs and the Oklahoma R&R Chair for Church Music. In addition to his responsibilities at UCO, he also serves as the director for the First Christian Church-Edmond Chancel Choir. When not directing music, he enjoys woodworking, baseball, travel, and spending time with his loving family.
Christy Shinn
Biography
Christy Shinn is the Director of Choirs at Jackson High School where she is about to begin her 30th year of teaching. She teaches Treble Choir, Boys Choir, Concert Choir, Women’s Choir, Adaptive Music, AP Music Theory, Advisory, and is the Department Chair. Prior to coming to Jackson High School, she taught 1 year at Crystal City Junior High & High School and also taught K-5th grade Elementary Music before moving into her current position. Mrs. Shinn is a 1993 graduate of Jackson High School and has a BME & MME from Southeast Missouri State University where she was the proud recipient of the Margaret Woods Allen Piano Scholarship. Mrs. Shinn has also been awarded the Jackson Chamber of Commerce Teacher of the Year award, the Rhodes 101 Outstanding Teacher of the Year, Teacher of the Year by the American Federation of Teachers, the MCDA Outstanding District Director Award, the JHS Football Teacher of the week, recognized by the local VFW as an Educator of Distinction for her efforts in the annual Veteran’s Day Program, nominated by her students as the graduation speaker, and featured in “She” Magazine. Mrs. Shinn has taken much pride in continuing to build the Jackson High School Choral Department.. Under her direction and the direction of her co-teacher for over 20 years, Beth St. John, who just happens to be her sister, sees over 350-400 students every semester. Mrs. Shinn is proud to be a part of the Jackson Music Department and a K-!2 Vertical Team that has incredibly talented and passionate teachers. Mrs. Shinn is also very active in the community as a church organist at Emanuel United Church of Christ in Jackson, a J-click leader at JHS working closely with the Traction program, a member of the Jackson High School Leadership Team, Jackson After School Kids Club Staff Member, and sought after accompanist, clinician and presenter for conferences and Professional Development. She is a very active volunteer in the Jackson Community. She has completed Orff levels at a Summer Institute at the University of Memphis and served several state roles such as, MCDA Recording Secretary and MMEA Choral Vice President and continues to be an active member of MMEA, MCDA, ACDA and MSTA. Mrs. Shinn’s students are widely recognized at the state and regional levels as being selected for MCDA, SWACDA and National Honors Choirs as well as her choirs receiving Exemplary Ratings at the MSHSAA State contest and having a record number of students chosen to the All-District Choir and Missouri All-State Choir every year. The JHS Concert Choir, under Mrs. Shinn’s direction, has also been chosen to perform at the MMEA State Convention, for the Governor in Jeff City and in collaborative concerts with the MSU Concert Chorale with Dr. Cameron LaBarr. The JHS choirs also perform in an annual Madrigal Feaste with 200 students in a weekend and over 840 guests, a large Community Veteran’s Day Program, and a Pop Concert which includes a cast of 220 students and seats over 1700 people in 4 shows. Anyone who knows Mr. Shinn knows that she is passionate about music but more than anything, she loves her kids and she loves what she does and does it with all she is. Mrs. Shinn is happily married to her husband of 29 years, Geoff, who just so happened to meet in the very choir room that she teaches in, and they have 3 beautiful children Hannah, who is married and finishing her Optometry degree at the University of Missouri at St.Louis, Lydia, who just graduated with a major in Elementary Education at Southeast Missouri State and will be teaching 4th grade this fall, and Gavin who will be a senior at Jackson High School. She has had the unique opportunity to have all three of her children in her choirs at JHS. She enjoys walking, reading, playing the piano, and spending time with her family. She credits her love of music and joy for life to her precious parents. She is grateful for every student that has graced her path, especially those reading this because they have found their life’s purpose in a music classroom.
Nyadia Thorpe
Biography
Nyadia Thorpe is a choral educator, conductor, worship musician, and adjudicator with nearly two decades of classroom teaching experience and more than 20 years of service in church and community music. She currently serves as Choir Director at Life High School Waxahachie and Director of Worship & Music at First Presbyterian Church Duncanville.
A graduate of the University of Texas at Arlington and Southern Methodist University, Nyadia is passionate about developing confident singers, inspiring student leadership, and equipping fellow educators with practical strategies for building successful choral programs. Her work reflects a commitment to excellence, servant leadership, collaboration, and creating meaningful experiences that strengthen schools, churches, and communities to achieve more together than thought possible.
Alexander Carr
Biography
Andy Waggoner
Biography
Andy Waggoner serves as Director of Worship Arts at Webster Hills UMC in Webster Groves, MO and is Artistic Director of the 240-member St. Louis County Community Chorus. He has served Missouri ACDA as R&R for Community Choirs and Music in Worship and currently serves in various capacities, mainly in welcoming new members and assisting with special events. Andy has prepared choruses and conducted residencies in London, Dublin, New York City, Washington DC, and festivals and tours throughout the Midwest. He has also prepared and sung in choirs for touring shows at the Fox theater, Sheldon Concert Hall, Stifel Theater and Scottrade Center, including artists such as Josh Groban, Fantasia, Barry Manilow and live video game concerts like Final Fantasy. He is grateful for the opportunity to serve SWACDA, an organization that has meant so much to him throughout his career.
Kristina MacMullen
Biography
Conductor-teacher Kristina Caswell MacMullen has devoted her career to sharing music and inspiration with students and audiences. Her collaborations with fellow musicians continue to confirm her abiding hope for the future and an unflagging belief in the power of choral music.
Currently, MacMullen serves as the Mary Gibbs Jones Chair of Music and Director of Choral Activities at Baylor University. She conducts the Baylor A Cappella Choir, Chamber Singers, and leads the graduate program in choral conducting. Prior to her appointment at BU, MacMullen served on the faculties of the University of North Texas and The Ohio State University. Her interdisciplinary work earned her the Sir William Osler Award at OSU and the President’s Special Recognition Award at UNT. MacMullen has also been recognized by TCDA for her innovation in programming.
MacMullen believes that great potential lies in choral performance and creative communication. She strives to guide her students, as they desire to make an impact for good. Creative projects include interdisciplinary performances addressing human trafficking, the Kubler-Ross stages of grief, play theory, Maslow’s hierarchy of needs, archetype exploration, belonging, American song, civic engagement, and the nature of tears.
As an active adjudicator and clinician, MacMullen has conducted All-State and honors choirs throughout the United States. She has presented and co-presented interest sessions at state, regional, national and international conferences. Her teaching and conducting is featured on the DVD Conducting-Teaching: Real World Strategies for Success published by GIA (2009). Her editions are published by Boosey & Hawkes, Musicatus Press, and MusicSpoke.
MacMullen earned both the Bachelor of Music Education and Master of Music degrees from Michigan State University. She completed the Doctor of Musical Arts degree at Texas Tech University. MacMullen has enjoyed a diverse career as a public-school teacher, interacting with students in rural, suburban, and urban settings, elementary through high school. She also sings with the professional ensemble Mirabai.
Yoojin Muhn
Biography
Dr. Yoojin Muhn is the Director of Choral Activities at the University of Texas at San Antonio (UTSA), where she conducts the UTSA Chamber Singers and teaches undergraduate and graduate choral conducting. She also serves as Music Director of the San Antonio Mastersingers. Recent guest engagements include conducting the 2025 Louisiana All-State Choir and conducting Fauré’s Requiem at Carnegie Hall in 2026 with Manhattan Concert Productions. Under her leadership, the UTSA Choirs have performed at Carnegie Hall and the 2025 National ACDA Conference, and the UTSA Chamber Singers were selected to perform at the 2026 Texas Music Educators Association Convention. Dr. Muhn holds degrees from the University of Southern California, the University of Cincinnati College-Conservatory of Music, Westminster Choir College, and SookMyung Women’s University in Seoul, South Korea.
Jabarie Glass
Biography
Jabarie Glass serves as Director of Choral Activities and Assistant Professor of Music at the University of Oklahoma, where he provides artistic and administrative leadership for the choral program, teaches graduate courses in conducting and score study, and conducts University Chorale. He previously served on the faculty of the University of South Carolina following nearly a decade of distinguished leadership in secondary choral music in Mississippi. Ensembles under his direction have performed by juried invitation at the American Choral Directors Association (ACDA) Southern Region Conference, the South Carolina Music Educators Association Conference, and the joint Mississippi-ACDA/Mississippi Music Educators Association Conference.
Glass maintains a national profile as a conductor, clinician, and scholar. An advocate for new music, he is committed to enriching the choral canon by commissioning and premiering works that embrace diverse artistic perspectives. He has shared practical and research-informed approaches to conducting, rehearsal technique, repertoire selection, and singer development through conference presentations, conducting masterclasses, professional development workshops, and publications in The Choral Journal. He remains deeply engaged in the musical development of young choral artists by conducting honor choirs across the United States. Recent engagements include the ACDA Southwestern Region 10–12 Mixed Choir and all-state choirs in Alabama, Georgia, Mississippi, North Carolina, South Carolina, and Wisconsin.
Glass’s commitment to the choral profession extends beyond his artistic and scholarly work through sustained leadership and service. He currently serves as Youth and Student Activities Repertoire and Resources Chair for ACDA Southwestern Region and as a member of the National Board of the National Collegiate Choral Organization. He has served as Student Activities Coordinator for ACDA Southern Region, in multiple Repertoire and Resources Chair roles for Mississippi-ACDA, and on conference planning and adjudication committees.
A native Mississippian, Glass earned dual bachelor’s degrees in business management and music education from the University of Mississippi, where he was inducted into the Student Hall of Fame, an honor awarded annually to ten seniors for exemplary leadership, scholarship, and service. He went on to earn a master’s degree in music education from the Florida State University College of Music and a doctoral degree in conducting from the University of Michigan School of Music, Theatre & Dance.
Mindy Bettridge
Biography
Mindy Bettridge serves as Choir Director at Owasso High School and Choral Department Chair for Owasso Public Schools in Oklahoma. With over 25 years of teaching experience spanning kindergarten through college, she is dedicated to cultivating musical excellence, fostering student leadership, and advancing choral education at all levels.
In addition to her work in public education, she has served as an adjunct faculty member at Oklahoma State University, teaching courses in Secondary Choral Methods and Choral Literature. She is actively engaged in Oklahoma’s choral music community as a member of Vox Solaris chamber choir and regularly adjudicates OSSAA Solo and Ensemble and Large Group district contests.
Under her direction, Owasso choirs have performed extensively both domestically and internationally, including three appearances at Carnegie Hall and performances at St. Patrick’s Cathedral in Dublin, Ireland. Her ensembles consistently earn superior ratings and Accent Awards at OSSAA State Choir Contests, reflecting a sustained commitment to artistic excellence and student achievement.
An active leader in professional organizations, she has served the Oklahoma Music Educators Association as Quad Chair, All-State Treble Choir Chair, and All-State Mixed Choir Chair. She is also a past president of the Northeastern Choral Directors Association, where she has worked to support and strengthen choral programs across northeastern Oklahoma.
Mindy holds a Bachelor of Music Education from the University of Nevada, Las Vegas and a Master of Science in Curriculum and Instruction from Oklahoma State University. As the SWACDA Repertoire and Resources Chair for Contemporary A Cappella Choirs, she is excited to support conductors, promote innovative programming, and foster artistic collaboration throughout the region.
Michael Shimp
Biography
Michael Shimp earned his Bachelor of Music in Vocal Performance from Southwestern Oklahoma State University in 2003 and began his operatic training with the Tulsa Opera Young Artist Program and Inspiration Point Fine Arts Colony in Eureka Springs, Arkansas. Now in his nineteenth year of teaching, Mr. Shimp has served as a choral music educator at Jenks High School in Jenks, Oklahoma, since 2018, following eleven years of teaching choral music in Owasso Public Schools from 2007 to 2018. Widely respected for his work in developing young singers, Mr. Shimp is also recognized for his leadership in organizing regional and state choral events. He currently serves as Quad Chair for the Oklahoma Music Educators Association Northeast All-State Region and has previously served as Vocal Jazz All-State Chair and Co-Chair for the Oklahoma Choral Directors Association, as well as State Co-Chair for the Oklahoma Children’s All-State Choir. From 2015 to 2024, he served Oklahoma Circle the State with Song as State Co-Chair, Region R Coordinator, and guest clinician. His additional clinician engagements include the East Central Oklahoma Choral Directors Association Regional Treble Choir and the Western Oklahoma Junior High Honor Choir. A member of the choral staff of the Oklahoma Ambassadors of Music since 2011, Mr. Shimp will travel with the organization on its European tour in the summer of 2027. His ensembles have twice been selected as Honor Groups for the Oklahoma Music Educators Association Convention, with his Owasso choir performing in 2014 and his Jenks Advanced Men’s Choir in 2022. He was named the 2010–2011 Teacher of the Year for the Owasso Sixth Grade Center. His professional memberships include NAfME, OkMEA, ACDA, and OCDA.
Eddie Vandewalker
Biography
Mr. Eddie Vandewalker is a native of Oklahoma and is a music educator, collaborative pianist, conductor, clinician, and church organist who has spent most of his career in Texas. He has served as an instructor of music at two-year colleges for 17 of the 30+ years he has been in education. Other teaching experience includes positions in high school choral music and at universities as choral conductor and professor of music education.
At two-year colleges Mr. Vandewalker conducted choirs, instrumental ensembles, and show groups, taught Music Theory, Aural Skills, Music Appreciation, and Applied Lessons in Voice and Piano, as well as directed many musical theater productions. He has also served as department chair in many instances.
During the summers Vandewalker often serves as All-State Choir Camp clinician at various camps across the state of Texas. He can also often be found playing piano for choral music reading sessions at the summer TCDA conventions.
Mr. Vandewalker’s college students have sung in the Texas Two-Year College All-State Choir, SWACDA College Honor Choirs, and National ACDA Honor Choirs. His high school choirs have earned UIL plaques, including sweepstakes. Many high school choir students have sung at the UIL state solo and ensemble contest, some winning Outstanding Soloist awards, and performed in TMEA District and Region Honor Choirs.
In 1989 he earned a Bachelor of Vocal Music Education/Piano Performance degree from East Central University in Ada, OK, in 2003 he earned a Master of Music degree from the University of Texas at Arlington. Mr. Vandewalker has been honored to study choral conducting with Jeff Frederick, Steve Walker, Jing-Ling Tam, Jerry McCoy, and Henry Gibbons.
Michael Murphy
Biography
Michael Murphy is the Director of Choral Activities and Professor of Music at Stephen F. Austin State University where he teaches choral conducting, ensembles, repertoire, and methods courses and oversees the graduate conducting program. Before his appointment to SFASU in 2017, Michael was Director of Choral Activities and Associate Professor at University of Idaho for nine years, where he was Founder and Artistic Director of the Idaho Bach Festival and was recognized with the UI Faculty Award for outstanding scholarship, teaching, and engagement.
Dr. Murphy is an active clinician, adjudicator, and author. His research interests include training and developing the holistic conductor, rehearsal techniques, new choral compositions, and investing and creating impactful connections in our global community through music. Murphy’s international conducting and teaching experiences include Austria, China, Czech Republic, England, Ecuador, Germany, Italy, Ireland, Norway, Panama, and Sweden. The Confucius Institute awarded Dr. Murphy with the “Understanding China Fellowship” and asked him to serve as visiting scholar at Sun Yat-sen University, South China University of Technology, and Guangzhou University of Foreign Studies.
Murphy is the co-author and editor of Conducting Primer in Practice, has been published several times in Choral Journal, and contributed to volume 4 of Teaching Music Through Performance in Choir. As a passionate champion of music for all, Michael has experience teaching all ages and levels and several auditioned and non-auditioned collegiate, community, school, and church choirs. His choirs have been invited to perform for several regional and state ACDA and NafME conferences, and he has held several international, national, and state leadership positions in WCCN, ICCF, ACDA, NAfME, and NCCO. Murphy received his degrees in conducting and choral music education from Florida State University and East Carolina University.
R&R COMMITTEE PURPOSE AND FUNCTION
The Repertoire and Resources (R&R) areas provide support, vision, and
resources for every major area of choral work. R & R chairs and
Coordinators are positioned to provide vital content through the following:
- Literature recommendations
- Resource presentation
- Conference-related curated events
- Year-long programming of professional development opportunities
- Collaboration between R & R leadership at the state, region and
- national levels
- Member support and encouragement
- Direct impact on membership
Repertoire and Resources Committee Coordinators and Chairs serve as
conductors, teachers, composers, and constituencies who share similar
interests. R & R Leaders possess demonstrated expertise in a specific
choral area and serve as leaders in the three primary efforts:
Collaboration
- Communication
- Commitment
It is our mission to form partnerships between R&R committees and the
ACDA national, regional, and state leaders through education, cooperation,
communication, and dedication in our unending quest for excellence in the
American Choral Directors Association.
Gretchen Harrison
National Repertoire and Resources Committee Chair
Revised 2023
