The perforated panel resonator with flexible tube bundles and its sound absorption measurements

This paper deals with a new type resonant absorber, i.e. the perforated panel resonator with flexible tube bundles. The acoustical properties of the new sound absorbing structure are measured and analyzed. From the measurement results and theoretical analysis, the following conclusions can be made. The incorporation of the tube bundles into the resonator absorber is helpful to improve its low frequency sound absorption. Because the artificial prolongation of air column length inside an hole neck will increase acoustic mass, so that the resonance frequency can be shifted to a lower frequency correspondingly. Compared with traditional perforated panel absorber, the acoustic resistance of the sound absorbing structure can be increased considerably due to the incorporation of the flexible tube bundles into the resonator absorber, so that higher sound absorption coefficients can be expected to reach. By reasonably utilizing the tube and cavity coupling resonances, the frequency bandwidth of sound absorption of the perforated panel resonator with flexible tube bundles may be broadened. The perforated panel resonator with flexible tube bundles may be used in some cases with strict space limitations and with the expectation of increasing the sound absorption at lower frequencies.