I won't go into jazz as it is well known the cuts has been altered and differed from the master tapes, it is known in detail for RVG and a few other engineers. However as I understand we are talking about classical here so here are some quotes by people who actually cut some of the classical records of Decca.
a quote from The Decca Sound: Secrets of the Engineers
“There were also compromises at the disc cutting stage which was another key factor in the Decca sound. Arthur Haddy was a fanatic about getting the sound on disc, but to make a stereo disc you had to cut the bass and blend it below 100Hz so that the vertical motion would not be too extreme for styli tracking. And they would cut at half speed in the early days to get the maximum number of Watts onto disc. The cutters were not helium cooled and the engineers were afraid that they might short out, which would be expensive to fix. You had to have the EQ network and get the tape playback to work properly, but it made a lot of sense to get all that sound without too much compromise.”
two quotes from ARSC journal Vol.18, No. 1-2-3 The Birth of Decca Stereo by Michael H. Gray (1986)
"Some important procedures were different. All stereo discs cut between 1957 and 1967 were half-speed mastered, including ones from Dolby master tapes using specially modified Dolby replay machines. Half-speed cutting helped control high-frequency distortion by moving the 8 KHz peak of the early Teldec head (and those of some later Neumann models) to a point around sixteen KHz. With improvements in high-frequency behavior there unfortunately came linearity and distortion problems at the low end, a factor which along with a thirty-Hertz "Kingsway filter" to eliminate that venue's subway rumble may account for the absence of really deep bass on many early Decca stereo discs."
"By 1968, Decca was using a new Neumann SX-68 cutting head. With the installation of a Neumann SX-74 cutting head in 1974 that was joined in 1981 by a VMS-80 cutting lathe, a system was created that was at last able to pass the full frequency and dynamic range of Decca's master tapes. Even with top-class cutters, however, Decca did not remain immune from the inconsistencies of vinyl disc production, so that a single well-cut lacquer could through plating and pressing create copies different enough to make statements about which pressings are good and which are not almost impossible to make."
a quote from the Transcript of interview conducted 17th October 2017 with engineer Stan Goodall, the engineer at Decca
I started to cut Mono LPs and I started cutting mono LPS with an engineer called Ron Mason who taught me how to do that. I remember he had rather big fingers but he was very delicate when used to put the cutting needle down cut the record he taught me how to cut Mono LPs. And because I was young and enthusiastic the new system the new sound system come on the block was stereo sound, in the old days it was double F double R which was full frequency recorded sound from fifty to fifteen thousand cycles and then when stereo came out it was double F double S full frequency stereophonic sound which used to emblazon the Decca label.
PS. if we really like to hear how the recordings actually sounded like, we would need the original three channel master tapes, a three channel tape player and a three channel stereo system. How I wish we could have these tapes in that format, I would go down the road to build the rest of the system just for 50 of these records. For analog it is near impossible to get these titles in 3 channel tapes but I remember on sacd's some of these three channel versions were released and I seriously considered going down that road and one day I still might as a second system just for that.
a quote from The Decca Sound: Secrets of the Engineers
“There were also compromises at the disc cutting stage which was another key factor in the Decca sound. Arthur Haddy was a fanatic about getting the sound on disc, but to make a stereo disc you had to cut the bass and blend it below 100Hz so that the vertical motion would not be too extreme for styli tracking. And they would cut at half speed in the early days to get the maximum number of Watts onto disc. The cutters were not helium cooled and the engineers were afraid that they might short out, which would be expensive to fix. You had to have the EQ network and get the tape playback to work properly, but it made a lot of sense to get all that sound without too much compromise.”
two quotes from ARSC journal Vol.18, No. 1-2-3 The Birth of Decca Stereo by Michael H. Gray (1986)
"Some important procedures were different. All stereo discs cut between 1957 and 1967 were half-speed mastered, including ones from Dolby master tapes using specially modified Dolby replay machines. Half-speed cutting helped control high-frequency distortion by moving the 8 KHz peak of the early Teldec head (and those of some later Neumann models) to a point around sixteen KHz. With improvements in high-frequency behavior there unfortunately came linearity and distortion problems at the low end, a factor which along with a thirty-Hertz "Kingsway filter" to eliminate that venue's subway rumble may account for the absence of really deep bass on many early Decca stereo discs."
"By 1968, Decca was using a new Neumann SX-68 cutting head. With the installation of a Neumann SX-74 cutting head in 1974 that was joined in 1981 by a VMS-80 cutting lathe, a system was created that was at last able to pass the full frequency and dynamic range of Decca's master tapes. Even with top-class cutters, however, Decca did not remain immune from the inconsistencies of vinyl disc production, so that a single well-cut lacquer could through plating and pressing create copies different enough to make statements about which pressings are good and which are not almost impossible to make."
a quote from the Transcript of interview conducted 17th October 2017 with engineer Stan Goodall, the engineer at Decca
I started to cut Mono LPs and I started cutting mono LPS with an engineer called Ron Mason who taught me how to do that. I remember he had rather big fingers but he was very delicate when used to put the cutting needle down cut the record he taught me how to cut Mono LPs. And because I was young and enthusiastic the new system the new sound system come on the block was stereo sound, in the old days it was double F double R which was full frequency recorded sound from fifty to fifteen thousand cycles and then when stereo came out it was double F double S full frequency stereophonic sound which used to emblazon the Decca label.
PS. if we really like to hear how the recordings actually sounded like, we would need the original three channel master tapes, a three channel tape player and a three channel stereo system. How I wish we could have these tapes in that format, I would go down the road to build the rest of the system just for 50 of these records. For analog it is near impossible to get these titles in 3 channel tapes but I remember on sacd's some of these three channel versions were released and I seriously considered going down that road and one day I still might as a second system just for that.
