SoundBender: Dynamic Acoustic Control Behind Obstacles

Ultrasound manipulation is growing in popularity in the HCI community with applications in haptics, on-body interaction, and levitation-based displays. Most of these applications share two key limitations: a) the complexity of the sound fields that can be produced is limited by the physical size of the transducers, and b) no obstacles can be present between the transducers and the control point. We present SoundBender, a hybrid system that overcomes these limitations by combining the versatility of phased arrays of Transducers (PATs) with the precision of acoustic metamaterials. In this paper, we explain our approach to design and implement such hybrid modulators (i.e. to create complex sound fields) and methods to manipulate the field dynamically (i.e. stretch, steer). We demonstrate our concept using self-bending beams enabling both levitation and tactile feedback around an obstacle and present example applications enabled by SoundBender.