Abstract: A sound absorption method based on the reflected sound of the least power is put forward. It takes piezoelectric materials as the main body material of the active sound absorption to absorb the sound with the active sound absorption principle. It past the piezoelectric ceramic on the thin simply support board through two microphones sensor which arranges in front of the simply supported board to test the incident sound waves and reflection sound waves. According to the detected reflection sound wave, the sound pressure which is produced by the wave and vibration of the simply support board adding the piezoelectric ceramic voltage is the total reflected sound pressure. At the condition of the least quadratic and the sum of the reflected sound pressure, the voltage is obtained which adds in the piezoelectric ceramic, so as to achieve the effect of sound absorption. The sound pressure quadratic sum theory of single piece of piezoelectric ceramic chips and more pieces of piezoelectric ceramic chips is designed. Numerical calculation and experiment are made according to the number of the piezoelectric ceramic chips for one, three and five etc. The results show that this method could have good active effect of sound absorption, and the effect is good when the number of piezoelectric ceramic chips is three. More piezoelectric ceramic chips could not made the sound absorption effect obvious increase.

Key words: Active sound absorption, Piezoelectric materials, Reflected sound pressure