01054374

Component

This paper describes how, because of the tireless efforts of engineering teams within the hard disk drive (HDD) industry, the levels of noise emissions from HDD’s has been significantly reduced to the point where customers are requiring transient events be limited in their emissions as well. To date, the standards available for noise emission measurements are limited to steady state events with some mention of impulsive events. However, nothing really addresses time varying events or events that would fall into the “quality of sound” with the exception of ISO532B. But even ISO532B addresses steady state time averaged loudness events using the Zwicker method. Transients that occur, such as latching and de-latching, can be characterized using standardized measurement techniques that are currently in place such as impulsiveness, loudness, and wavelet analysis. Specifically one area of a HDD operation has proven to be hard to characterize, yet has garnered much criticism from customers. That area is the run up and down of the spindle motor as the drive is powered up/shut down or put on standby/awakened from standby. The section of drive consumers that is making this complaint more often is the market where the drives are operated in a very quiet environment (PVR’s, DVR’s, etc). During the spin up cycle some people have described certain events as whiny and hissy in drives that had unacceptable spin ups. Jury tests were conducted to try and find out which time histories were acceptable and which were not. Separate analyses were performed to show what the differences are between the good and the bad. It should be noted that to the HDD industry, characterization during R&D stages is much different than characterization on a mass level during production stages. Sampling at the factory level can reach the 100% mark depending on the customer, market conditions, etc. When the factory turns out X million units per quarter, a quick and efficient method must be found and employed when taking and analyzing data at this level of throughput.

01054353

English

pp 785-794

2004

Noise-Con 04. The 2004 National Conference on Noise Control Engineering

CD-ROM

Figures (13) ; References (6)

CD-ROM; Computers; Hard disks; Loudness; Noise control; Noise sources; Sound level meters; Sound transmission; Wavelets

Energy; Environment; Highways; I15: Environment

TRIS, TRB

Jul 26 2007 12:18PM