Western Kentucky University
Department of Physics and Astronomy


Dr. Brian Holmes

Department of Physics and Astronomy
San Jose State University

"The Physics of Brass Musical Instruments"

March 18, 2019 @ 4:00 pm in EST 260

About the Speaker

Brian Holmes received a BA from Pomona College and a PhD (in experimental low temperature physics) from Boston University. He has been a faculty member at Worcester Polytechnic Institute, Hunter College and San Jose State University. He has published articles on magnetism in solids at low temperatures; photo refractive materials; the physics of sports; and the physics of music. In addition to teaching in the Physics Department, he has taught in the Music, Teacher Education, and Creative Arts Departments. He has given over 150 invited talks on the physics of musical instruments. He retired from San Jose State University in 2017. He has also been active professionally as a horn player, performing with the Boston Ballet, the San Jose Symphony, and Opera San Jose. He is also a composer, writing mostly for chorus or solo voice. He has published 30 works, has completed about 25 commissions, and has won various prizes and awards, most notably the 2012 American Prize in Choral Composition.


Brass musical instruments include a cup-shaped mouthpiece, a conical lead pipe, a cylindrical section (usually with slides or valves), and a flared bell. It is natural to imagine that the bell is designed to project sound from inside the instrument. I will show, however, that only a tiny portion of the sound reaches the outside; the rest reflects from the bell, returning to the player’s lips. I will show why brass instruments rely on valves and slides, rather than the side holes used by woodwinds. I will explain why horn players keep their right hands in the bell of the instrument. The talk will be suitable for general audiences and will include many demonstrations. I will keep the physicists in the audience awake by explaining that the equation describing sound in a trumpet is the same as Schrödinger’s wave equation; that the penetration of sound through the bell resembles quantum mechanical tunneling; that a trumpet is like a laser.