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How to Preserve

Why Well-Transferred Magnetic Masters Still Sound Wrong

Featured image taken from The Miracle of Todd-AO, 1958

Why do well-transferred magnetic sound recording masters still sometimes sound "wrong" or fail to match a reference release print?

In a new white paper on the subject, sound expert and Endpoint Audio Labs founder Nicholas Bergh takes a deep dive into the "secret world" of Hollywood frequency standards prior to the 1980s, before Hollywood masters were recorded with the modern Society of Motion Picture and Television Engineers playback equalization curve. The industry's slow adoption not only of an overarching equalization standard for magnetic recording, but of the very recording technology itself, yielded 30 years of wild-west practices and applications that can be difficult to navigate today.

"If one takes the time to transfer a mag in a way that compensates for deterioration issues as well as correctly compensates for the recording EQ curve used, it is possible to hear a mag very close to how it was heard originally on the mix stage through the entire film," Bergh writes.

The study gives a concise historical overview of magnetic recording, an encroaching technology that became viable for professional use shortly after World War II and was adopted quickly by the broadcast and music sectors. The film industry had a longer road there, due to a variety of reasons including the widespread use of optical sound editing that was already in place in the 1950s, an abundance of optical sound library material at the time, and a workflow built on interlocking systems for synchronization and mixing.

As Hollywood studios slowly took to the new tech, other variables made industry synchronicity next to impossible. Equipment was leased from one of two companies early on, Western Electric (Westrex) or RCA, and each had different perspectives on best practices. There was also very little documentation about the curves being used internally, and of course each studio had its own philosophies and spirit of modification.

Bergh also references a 1970 Glen Glenn Studios analysis of legacy recording curves, the most comprehensive one on record, and the painstaking process of achieving fidelity to those curves when transferring mags today. It's a worthy endeavor, even as today's digital tools make it tempting to speed through the process.

"Most often these days, raw audio transfers go directly to a digital restoration stage, so the preservation or the original raw art object is not always considered as important," Bergh writes. "In other words, there is often a 'fix it in post' mentality when dealing with equalization and deterioration. However, when a master mag is transferred carefully, it can sound stunning. It is possible to hear (and preserve) a mix on its own terms before modern digital restoration and reformatting for commercial re-release."

Nicholas Bergh has worked in the audio space for nearly 30 years with experience in remote recordings, music mastering, and sound restoration for home market distribution. In 2003 he started Endpoint Audio Labs with a focus on improving the quality of digital restorations from the analog side. He is a member of the Academy's Sci-Tech Council Historical Subcommittee as well as the Society of Motion Picture and Television Engineers (SMPTE), the Audio Engineering Society (AES), the Association of Moving Image Archivists (AMIA), and the Association for Recorded Sound Collections (ARSC). He has presented a variety of papers on subjects, including the birth of electrical recording, multi-track optical recording in film, wax cylinder playback, and the technical history of RCA/Victor studios.

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