Isolating a computer or hard drive always has potential for sonic improvement whether the computer is in close proximity to the rest of the audio system or not. Potential, that is; in some cases isolating the computer will have little or no sonic effect, though sometimes improvements can be quite profound. In the digital realm, reducing the effects of micro-vibrations helps to keep error corrections at a minimum and optimizes phase/time relationships, keeping everything closer to real-time continuity and a more natural sound as the end result. With fine music reproduction, it's not really as simple as just x's and o's. Capacitors, microprocessors and other electronic parts are very sensitive to micro-vibrations, which in a light-speed and micro environment world have an effect on the end result of music that's to be ultimately converted to analog. Typically, micro (really, extremely micro) delays or alterations in data-flow timing and other computer processing stages produces glare and other anomalies in the music.
Herbie's Audio Lab