Time reversal focusing of high amplitude sound in a reverberation chamber: Optimizing the placement of transducers

Time reversal (TR) is a signal processing technique that may be used to intentionally generate high amplitude focusing of sound. The use of time reversal in room acoustics has been studied previously, but an analysis of the dependence of spatial positioning of the transducers in the room, and its effect on high amplitude focus signals has not previously been explored. Experiments are carried out in two reverberation chambers of differing size with eight compression drivers. Using these drivers, the impulse response is found and reversed in time. The spatial dependence of the transducers position is measured by calculating the time reversed impulse response at various transducer positions and then measuring the peak focal amplitude generated when the time reversed signal is broadcast to those positions. Multiple measurements suggest that the amplitude of the focus signal changes with both room size and proximity to a reflecting surface in the chambers.Time reversal (TR) is a signal processing technique that may be used to intentionally generate high amplitude focusing of sound. The use of time reversal in room acoustics has been studied previously, but an analysis of the dependence of spatial positioning of the transducers in the room, and its effect on high amplitude focus signals has not previously been explored. Experiments are carried out in two reverberation chambers of differing size with eight compression drivers. Using these drivers, the impulse response is found and reversed in time. The spatial dependence of the transducers position is measured by calculating the time reversed impulse response at various transducer positions and then measuring the peak focal amplitude generated when the time reversed signal is broadcast to those positions. Multiple measurements suggest that the amplitude of the focus signal changes with both room size and proximity to a reflecting surface in the chambers.