MOTM

I remember the cable tests quite well.
More recently there have been some double blind tests of material 
recorded at different sample rates.  I believe the panel consisted 
of highly regarded mastering engineers.

Although these individuals had no trouble recognizing the higher 
quality of 24 bits over 16 bits, they could not hear an appreciable 
difference between the standard 44.1 kHz sample rate used by CDs and 
the higher 96 kHz and even 192 kHz sample rates.

I have read some equipment reviews which raved about the improved 
quality of higher sample rates, but these were not double blind 
studies.  Personally I think the reason some higher sample rate 
converters sound better is the quality of the filters, not the rate 
of conversion.  For instance my Apogee Special Edition converters 
sound way better than my Digidesign converters both at 44.1 kHz.

The Nyquist criterion states that any sample rate of more than twice 
the highest frequency is all thats needed for accurate reproduction, 
and I refuse to believe that there are that many engineers who can 
hear over 20 kHz.  I sure can't now and I never could.