Ah.. Bunny I am shocked. It is so rare that I know something about Classical that you don't. Actually I realize that you probably knew this and that you just misspoke. Since my office is where the SACD remasters are being done I have learned something about these recordings.
My greatest perk over the last couple of years is that I have been able to listen to the original session tapes of many of these recordings.
"ON OCTOBER 6, 1953, RCA VICTOR MADE ITS FIRST EXPERIMENTAL "BINAURAL" RECORDINGS. AT NEW YORK'S MANHATTAN CENTER, LEOPOLD STOKOWSKI CONDUCTED A PICK-UP ORCHESTRA IN ENESCO'S ROUMANIAN RHAPSODY NO. 1 AND TCHAIKOVSKY'S WALTZ FROM EUGENE ONEGIN. IN DECEMBER RCA CONTINUED STEREO TESTS IN MANHATTAN CENTER WITH PIERRE MONTEUX AND MEMBERS OF THE BOSTON SYMPHONY ORCHESTRA. THEN, IN FEBRUARY 1954, RCA TOOK EQUIPMENT TO BOSTONS SYMPHONY HALL, WHERE CHARLES MUNCH AND THE BOSTON SYMPHONY WERE RECORDING BERLIOZ'S THE DAMNATION OF FAUST. FOR THE FIRST TIME, RCA ENGINEERS CAPTURED THE PERFORMANCE ON BOTH MONO AND TWO-TRACK TAPE. THESE EXPERIMENTS, COMBINED WITH FURTHER TECHNOLOGICAL REFINEMENTS EMPLOYED IN CHICAGO'S ORCHESTRA HALL IN MARCH 1954, WERE THE FIRST FORAYS INTO THE WORLD OF STEREO.
AT THE TIME THAT RCA INITIATED MULTI-TRACK SESSIONS, DISC MASTERING AND CONSUMER PLAYBACK TECHNOLOGY WERE MONAURAL. RCA VICTOR PROCEEDED TO USE TWO- AND THREE-TRACK EQUIPMENT TO RECORD THE WORLD'S GREATEST ARTISTS--HEIFETZ, PIATIGORSKY, REINER, MUNCH, RUBINSTEIN, FIEDLER--IN ANTICIPATION THAT HOME TECHNOLOGY WOULD CATCH UP TO STEREO SOUND. FINALLY, IN 1955, 1/4" 7 1/2IPS STEREOPHONIC TAPE PLAYERS ARRIVED ON THE CONSUMER MARKET, AND RCA RELEASED ITS FIRST STEREO ORTHOPHONIC TAPES.
STEREO ORTHOPHONIC TAPES REDEFINED HIGH FIDELITY. IN 1958, THE WESTERN ELECTRIC COMPANY PRODUCED THE BREAKTHROUGH WESTREX STEREO DISC CUTTER, THEREBY REVOLUTIONIZING MASTER DISC PRODUCTION. STEREO PLAYBACK EQUIPMENT WAS DEVELOPED TO COINCIDE WITH THE NEW DISC CUTTING TECHNOLOGY. THE SAME YEAR, LIVING STEREO LP RECORDS WERE LAUNCHED, USHERING IN THE GOLDEN AGE OF STEREO HIGH FIDELITY.
RCA VICTOR'S FIRST TWO-TRACK SESSIONS IN LATE 1953 AND EARLY 1954 WERE CAPTURED ON PROPRIETARY RCA RT-21 1/4" 30 IPS TAPE MACHINES, WIRED TO A PAIR OF MONO MIXERS, EACH DEDICATED TO ONE TAPE TRACK. NEUMANN U-47 CARDIOID AND M-49/50 OMNIDIRECTIONAL MICROPHONES WERE FAVORED, AS WERE RCA-DESIGNED LC-1A 15" DUO-CONE SPEAKERS IN THE CONTROL ROOM. THREE TRACK RECORDINGS WERE REALIZED ON TUBE AMPLIFIER AMPEX 300-3 1/2" MACHINES RUNNING AT 15IPS AND IN LATER YEARS AT 30IPS, AND WERE MIXED DOWN TO 1/4" TWO-TRACK MASTERS. NO EQUALIZATION WAS USED IN THE ORIGINAL TRACKING PROCESS; THE MICROPHONE SIGNALS WERE SUMMED THROUGH PASSIVE ELECTRONICS AND PRINTED STRAIGHT TO TAPE. IN ADDITION, NO EQUALIZATION WAS USED TO ALTER PLAYBACK TAKES FOR ARTIST APPROVAL."
http://www.livingstereo-sacd.com/index.jsp