Noise-Level Reduction of a Slim-Type Optical Disk Drive Using the Idea of a Helmholtz Resonator

In this study, we have introduced a new attempt to reduce the noise level of a slim-type optical disk drive (ODD) using the concept of a Helmholtz resonator, which is a container with a neck through which the air can flow in and out. The Helmholtz resonator is known to generate a resonant sound when we apply disturbances across the opening of the neck but it is also known to absorb the acoustic noise to some extent, especially the noise of resonant frequency. The resonator is realized in the ODD using a tray, which carries a disk. A tray is prepared with various sizes of holes and hole configurations. The experimental results show that the total sound pressure level (SPL) can be reduced by more than 1.5 dB when a compound resonator type is employed.