Vox Alia, BIS, Channel Classics, Harmonia Mundi, Astree, CPO, Chandos, Pentatone. . . there are plenty of labels that do terrific sounding classical recordings. Even the big labels like Sony, DG, etc. make nice sounding recordings. Many of the older LPs on such labels as DG sounded pretty crappy to me--thin and bright (e.g., 1970's DG recordings) and actually sound better in CD reissue form. Classical is one of the few genres where recording quality in the digital era sounds quite good to me. I listen mostly to my 3,000+ CDs of classical music much more than I do listening to my LPs of classical music.
