Sbleam - the longer cable is required for good performance of ANY digital cable, USB, S/PDIF, Firewire or I2S.
The length requirement has to do with signal reflections, a digital-specific phenomena and issue. Read this white-paper for an analysis:
http://www.positive-feedback.com/Issue14/spdif.htm
This has been independently verified through AB/X tests by UHF magazine in Canada.
Now if the cable is less than 8 inches, this is also good, but not very practical.
Steve N.
Empirical Audio
The length requirement has to do with signal reflections, a digital-specific phenomena and issue. Read this white-paper for an analysis:
http://www.positive-feedback.com/Issue14/spdif.htm
This has been independently verified through AB/X tests by UHF magazine in Canada.
Now if the cable is less than 8 inches, this is also good, but not very practical.
Steve N.
Empirical Audio