Advancements toward a high-power, carbon nanotube, thin-film loudspeaker

The carbon nanotube (CNT) thermophone has been explored as a novel loudspeaker. Potential advantages of this technology in the audio industry include ultra-lightweight, low production cost, compact size, and independence from rare-earth materials. In this paper, progress toward a practical CNT loudspeaker is presented. Large, high quality CNT thin-film assemblies are designed and built. Design guidance for these types of assemblies is provided. Maximum sound output level, total harmonic distortion, and power efficiency tests are performed. A maximum source level of 111 dBA at 1 m is achieved at 2 kHz with the new sources. The main hurdle to this technology remains power efficiency. Several paths forward are discussed as this technology continues to advance to a position where it may be able to compete with current state-of-the-art, moving-coil loudspeakers.