School of Engineering


Correlation Study and Control of Mechanical Vibration and Psycho-Acoustic Parameters in Hard Disk Drive

In the hard drive industry, hard disk drive acoustics are becoming important. With the introduction of hard drives into new emerging markets in which the consumer is more keenly aware of and sensitive to radiated acoustic noise issues caused by vibration, engineers are facing great challenges to meet customer demands. Drive manufacturers are under severe cost constraints, many times unable to incorporate all the noise control devices necessary to make drives quieter.  

However, it is well understood that the mechanical noises come from vibrations; however, hearing is not a purely mechanical phenomenon of wave propagation but is also a sensory and perceptual event or we called psychoacoustic. In other words, when a person hears a sound, it arrives at the ear as a mechanical sound wave travelling through the air, whereas inside the ear it is transformed into neural action potentials. These nerve pulses then travel to the brain where they are sensed. In HDD field, there are three psychoacoustic parameters namely:1) Loudness  2) Sharpness, and 3) Pure Tone. These parameters need to be measured with high sensitivity microphones in an environment with lowest background noise while the mechanical vibration will be measured by attaching an accelerometer on the HDD casing under most of environment. To accomplish this, a detailed technical understanding and control of psychoacoustics and mechanical vibration are essential to successfully developing psychoacoustic control strategies on hard disk drive.