Lokkerman
19 Jan 2023
The Original Sound Of a Production Master Tape
Many Years ago I got passed a Hard Disk Drive full of recordings purportedly from Production Mastertapes.
For those who don't know, the Production Master, or sometimes known as the Distribution Master, was a direct copy of an original master tape and was used to make a vinyl, reel to reel or cassette duplication master. i.e. the master for the various mediums that we used to listen to music from, in the pre-digital times.
It should be the ultimate in sound, as all the recordings that we once listened to, originated from this source or a very close relative.
These tapes were found in an old recording studio in NYC, due to be converted to domestic dwellings. Incredibly, these tapes were all scrapped.
Fortunately, the engineer in charge of decommisioning the studio equipment, had the vision to take an archival copy in digital format before they were destroyed. He used the studio mastering machine, an Ampex ATR-102 to make the transfers.
The first six Led Zeppelin albums were included in this tranche. However they always sounded odd and it wasn't until almost ten years after they were given to me that I revisted them. This time I instantly recognised the problem; they were on tape mastered for the UK/Europe market; therefore the tape equalisation [EQ] (remember that with cassette?) was set to be replayed back on a machine setup for IEC standard playback.
The studio machine was set up to playback NAB (US standard equalisation for tapes).
Fortunately, with all things analogue, there was a way to rectify this. There is a Magnetic Reference Laboratory, that retains such items as conversion tables (https://www.mrltapes.com/) and I was able to construct a (FIR) filter to make a conversion in my DAW back to how it should have been played back.
Wow! maybe the definitive versions of how the analogue recordings should have sounded.
Because of copyright issues, these have not been shared but if you are lucky enough to hear them, (some early versions got copied without my knowledge) then you are in for a treat.