Thank you Sbank. Let me give small example why bits are not the bits.
When we attempt to do something very simple like sending digital signal representing 1kHz we might actually receive three different signals. It is because in order to produce only 1kHz D/A converter would have to receive digital words in precisely exact intervals. Any variation would create additional signals - sidebands. Imagine that digital transmission of this 1kHz signal jitters in time because of 60Hz noise. That would create additional 940Hz and 1060Hz signals - most likely very small but audible, being not harmonically related to 1kHz. Amplitude of these sidebands would be proportional to time variation from ideal moment of delivery while frequency would be difference from 1kHz by how often this variation happens (in this case 60 times a second). Since music is not just simple 1kHz signal but a lot of them time jitter of digital signal will create a lot of additional frequencies - a noise, proportional in amplitude to amplitude of original signal (and undetectable without it).
When we attempt to do something very simple like sending digital signal representing 1kHz we might actually receive three different signals. It is because in order to produce only 1kHz D/A converter would have to receive digital words in precisely exact intervals. Any variation would create additional signals - sidebands. Imagine that digital transmission of this 1kHz signal jitters in time because of 60Hz noise. That would create additional 940Hz and 1060Hz signals - most likely very small but audible, being not harmonically related to 1kHz. Amplitude of these sidebands would be proportional to time variation from ideal moment of delivery while frequency would be difference from 1kHz by how often this variation happens (in this case 60 times a second). Since music is not just simple 1kHz signal but a lot of them time jitter of digital signal will create a lot of additional frequencies - a noise, proportional in amplitude to amplitude of original signal (and undetectable without it).