There exists a widespread belief that digital low-pass filters introduce an audible ringing effect when applied to music. We investigate the phenomenon.

A frequent claim by detractors of digital audio is that the time resolution is equal to the sampling interval, 22.7 μs for the CD format. This is incorrect. Although there is a limit, it is much smaller, and it does not depend on the sample rate.

Over the years, various enhancements to the CD format have been marketed with promises of higher sound quality through the use of superior materials. One of the more recent entrants is UHQCD. We examine the performance of a CD player while playing such a disc.