Speaking strictly about classical recordings, RCA record 1/4", mono, 30 ips from 1949 until 1956, when they switched to 15 ips.  They recorded simultaneous, 1/4", two-track, 30 ips of orchestral recordings only, from 1953 (two experiments that I know of) until 1955, when they started recording all orchestral recordings two-track (eliminating the mono redundancy).  Starting in October 1956 or so, RCA recorded orchestras on 1/2", three-track tapes at 15 ips.  Starting around April 1958, RCA recorded everything three-track, 15 ips, except for those recordings made for RCA in England by Decca.  The Decca-sourced originals were recorded two-track, 15 ips.  Starting somewhere between September and November 1958, all RCA three-tracks were made using the AME curve, which lasted until sometime between December 1961 (the last tapes I found) and March 1962.  Starting from about March 1962, RCA switched to 30 ips on their three-track tapes.  Starting in 1968,
 RCA starting recording 1/2", 4-track, 30 ips, although three-track recording didn't stop until 1970.  Starting in 1970 or 1971 and going to at least 1976, RCA starting recording 1", 8-track, 15 ips Dolby A encoded tapes.  Prior to that, Dolby A encoding was not consistent.  Starting in 1972 (I think), RCA starting recording 2", 16-track, 15 ips, Dolby A encoded.

Jon Samuels



On Wednesday, March 26, 2014 8:54 AM, "Gray, Mike" <[log in to unmask]> wrote:
 
Capitol in Hollywood: 

Three-track was in place as early as the move into the Tower in early 1956. 

The setup for classical in Goldwyn Stage 7 originally consisted on a trio of mikes, one per track, first hanging from a bar above and behind the podium, thereafter a trio on mike booms, facing left, center and right. This was the setup used by Hugh Davies. 
Carson Taylor, who did the later (post '59) records used a different setup. 

Since the tracks recorded were dry, they were sweetened in the mix to two tracks, which were used to cut the LPs. 

At the Tower, tracks were recorded dry with echo added in the mix from the chambers out in the parking lot. 

The Ring: 

Rheingold and Siegfried were recorded direct to two-track - the LPs were cut from these tapes, which now exhibit oxide shedding and wear at the splices; 

Walküre and Götterdämmerung had multi-track back-ups, and takes from these tapes have been used for the latest 
A/D transfer. Gentle NR was applied to all transfers. 

Mike Gray