Easy to answer this. July 21st 1955 - Elvis laid down the monumental Trying To Get To You. One of the worst quality surviving Sun tapes, the master no longer exists (some releases have used a mint Sun 78 as the source) but Sony has restored this as much as possible, and has created a new digital master from a transter to an RCA IPS 30 tape, however, it's still full of compression from tape wear, age and rubbish DR compression applied by RCA in 1956 for release on the eponymous LP "Elvis Presley'. Trying To Get To You is the first Elvis recording to feature a piano - played by Elvis himself - but it is inaudible as it wasn't miked correctly (and not erased by Sam Phillips as was long thought). You can however hear the vestiges of Elvis playing through leakage on the slapback dry echo tape - but you need a damned transparent and revealing hifi to hear it. You could argue if your hifi can't produce the piano, then it's not hifi as it's on the tape. I guarantee few hifis can reveal it...
And I can hear it - not sure why I'm feeling so pleased with myself.