Speaker system with 100-W high output power and 0.17% THD using 9-V power supply with digitally direct-driven technique

Abstract

In recent years, high-quality and high-efficiency speaker systems and high-image-quality televisions and monitors have grown in importance. However, to improve sound quality, implemented electric circuits increase in size and consume more power. In addition, efficiency at low output power and total harmonic distortion (THD) at high output are degraded. In this paper, we report on a small speaker system that can output 110 W and higher from an 9-V input without using analog circuits such as a D/A converter or a power amplifier. Using only digital processing, we build a low-power, fully digital speaker using a digital direct-driven speaker system (DDDSP) that can achieve high efficiency, low noise (by increasing the number of speaker units), and low THD. With this system, a high-quality and low-power-consumption speaker system can be used at home and at amusement facilities.