Very well recorded classical piano, provided it's "big" piano music like Beethoven or Liszt. Speakers Corner reissue of Clifford Curzon playing Liszt is my toughest piano LP. Ashkenazy/Beethoven sonatas on English pressed Decca/London is not quite as tough, but close.
Very well recorded operatic tenors and baritones. Operas on German EMI are the toughest-to-track LP's I own.
Very well recorded operatic tenors and baritones. Operas on German EMI are the toughest-to-track LP's I own.