Abstract by Carla Butts

Personal Infomation

Presenter's Name

Carla Butts

Degree Level


Abstract Infomation


Physics and Astronomy

Faculty Advisor

Brian Anderson


Plan for the creation of a virtual sound source using time reversal focusing of ultrasound in a room


What if you could create a virtual sound source in a room, without any physical object at the source location? Using ultrasound (frequencies of sound above the range of human hearing) and a technique called Time Reversal (TR), this could be possible. TR is a method of focusing waves to any selected location in a room, where the waves constructively interfere. Using audible sound in a room, it has previously been shown that it is possible to create a TR focus which is loud enough to create nonlinear effects. Nonlinear effects are important because nonlinear propagation of two ultrasonic sine waves has been shown to generate an audible difference frequency. Commercial sound sources, scientifically termed parametric arrays, have been manufactured to provide this difference frequency generation. This presentation will lay out our plan to focus two ultrasonic signals at the same location, in the hopes that this focused sound is loud enough to create an audible difference frequency signal. This would create audible sound seeming to come out of nowhere. This research provides a cross between ventriloquism and virtual reality.