Engineers spent more than four years on the catalog remastering . Group tried to stay as close to original as possible , yet clean up digitally . Probably the only surprise is that when I started buying the vinyl in the '60s , I bought stereo , so I had never heard mono , and to be honest with you One of the biggest challenges : hearing the mono versions .
Engineers spent more than four years on the catalog remastering . Group tried to stay as close to original as possible , yet clean up digitally . One of the biggest challenges : hearing the mono versions .