Quiet Case Basics and Recommendations

SPCR has just overhauled their guide on what it takes to keep a PC case quiet.  They cover regular PCs and even give special attention to the needs of the HTPC community.  The breadth of coverage (case, drives, materials, etc.) is quite impressive and well worth taking the time to read.

SilentPCReview

One poorly understood aspect of PC noise is cavity resonance. The air in a mostly enclosed box exhibits resonances centered at certain frequency points. Any noise that falls close to these resonance points become accentuated and amplified. Note that this does not have to do with any panel vibration at all, but the vibration of the air in the cavity — hence the term cavity resonance.