Taking us all off-piste for a second...try this website. Have bought numerous Furtwangler, and nearly all of the historic blues...really impressive work.
https://www.pristineclassical.com/
An excerpt to describe their work:
"Casals' finest recordings as never heard before
XR remastering strips away the decades to reveal incredible detail and nuance
When one considers all of the recordings made in the post-1925 electrical recording era, but before the development of full frequency range recordings in the 1940s, there can be few instruments more suited to the restrictions of the technology at the time than the cello. The range of frequencies required to capture it well, thanks to its low register, generally falls within the capabilities of 1930 disc recording, and this makes it a prime candidate for XR remastering. I've already had considerable success with Casals - his 1938 recording of the Dvorák Cello Concerto (PASC 246) beat all others, old and new, to become Gramophone's recommended recording of the work in February 2011.
However, nothing prepared me for the possibilities lying hidden in the grooves of his Cello Suites recordings of 1936 to 1939, which have surpassed all expectations. I was already familiar with issues on both EMI and Naxos (the latter a considerable improvement on the former), but neither offers the listener the full-bodied tone of Casals' cello, the crispness of his sound, the sense of immediacy and clarity which lay hidden in these recordings for so many decades.
My first task was to take the disparate recordings and bring some homogeneity to the sound of the instrument - each suite was initially processed separately, using a common reference in order to iron out differences in the recording equipment and locations used during the recording sessions. Thereafter I brought them together to continue what was at times a tricky restoration - revealing so much musical detail also reveals much else that is unwanted. Occasionally this may still be heard, but it should not distract you from one of the most remarkable restorations it has been my pleasure to undertake.
Andrew Rose"