New high fidelity (hi-fi) three-dimensional thermophone CNT sponge

A novel, high-fidelity (hi-fi) thermophone based on three-dimensional porous CNT sponge is designed for attachable and wearable sound generation devices. In addition to its simple structure and easy fabrication, CNT sponge thermophone exhibits excellent thermoacoustic and mechanical characteristics, particularly its wideband frequency response, due to its highly efficient energy conversion capability through the CNT nano-structural materials. In this paper, the hi-fi sound response of suspended CNT sponge thermophones is analyzed by theory and experiment. A theoretical thermoacoustic model for CNT sponge thermophone is proposed and the corresponding analytical solutions are established. To explore applications of CNT sponges, a flexible thermophone and a hi-fi thermoacoustic loudspeaker are developed and investigated by experiment. The flexible CNT sponge thermophone presents stable sound response before and after it is attached to some complicated surfaces. The CNT sponge thermoacoustic loudspeaker shows a wide bandwidth, high-quality audio output, and stable sound response. Such premium characteristics ensure its feasibility as a potential replacement for the conventional voice coil and piezoelectric loudspeakers.