Comment by speak_on

44.1 is "enough" only in theory. This assumes a physically impossible steep filter. Realistically, frequencies around 20 kHz will create audible artifacts (aliasing). So yes, a trained ear can tell the diffrenece between 44.1 and even 48 kHz. Like many other commenters in this thread, you are mixing up math theory with physical limitations of AD/DA converters. Oversampling is a common way to address this limitation, but strictly speaking 44.1 kHz is not as obviously "enough" as it seems.