Acoustic quieting
Acoustic quieting is the process of making machinery quieter by damping vibrations to prevent them from reaching the observer. Machinery vibrates, causing sound waves in air, hydroacoustic waves in water, and mechanical stresses in solid matter. Quieting is achieved by absorbing the vibrational energy or minimizing the source of the vibration. It may also be redirected away from the observer. One of the major reasons for the development of acoustic quieting techniques was for making submarines difficult to detect by sonar. This military goal of the mid- and late-twentieth century allowed the technology to be adapted to many industries and products, such as computers (e.g. hard drive technology), automobiles (e.g. motor mounts), and even sporting goods (e.g. golf clubs). Aspects of acoustic quieting When the goal is acoustic quieting, a number of different aspects might be considered. Each aspect of acoustics can be taken alone or in concert so that the end result is that the reception of noise by the observer is minimized. Acoustic quieting might consider... Noise generation: by limiting the noise at its source, Sympathetic vibrations: by acoustic decoupling, Resonations: by acoustic damping or changing the size of the resonator, Sound transmissions: by reducing transmission using many