Remastering and Audio Restoration at Abbey Road Studios

Remastering and Audio Restoration at Abbey Road Studios

Date: 11 May 2010
Time: 18:30

Location: Royal Academy of Engineering
3 Carlton House Terrace
London SW1Y 5DG

See below for location map.

Lecture by Simon Gibson of Abbey Road Studios


EMI has an archive going back to 1898 and, since Abbey Road Studios opened in 1931, there has been a gradual increase in the remastering of that back catalogue for new formats. Starting with a potted history of EMI, the early years of recording and the work of Alan Blumlein, we move on to the emergence of remastering at Abbey Road and the systems and techniques used today. The talk will then concentrate on the use made of CEDAR Audio’s Retouch software in the audio restoration of The Beatles album remasters as well as its more usual use in the creation of music for the video game The Beatles Rockband. Along the way we will hear rare audio extracts from EMI’s archive and clips from The Beatles’ recordings to demonstrate these remastering and restoration techniques.

We regret that due to the large amount of copyrighted material played during this lecture we are unable to provide a recording.

Lecture report

Simon’s work at Abbey Road Studios focuses on audio restoration. Much of this is for EMI’s own vast catalogue, which dates back to the first recording by The Gramophone Company (EMI’s predecessor) in 1898. EMI’s archive comprises hundreds of thousands of items, not just audio discs and tapes but also artwork, photographic records and other materials.

In the case of recordings from the pre-tape era, the preference is to transcribe from the metal masters as these deliver a superior quality to a shellac disc. Before 1925 there was no 78rpm standard so the only way to set the correct playback speed is by musical pitch. 1925 also saw the introduction of electrical recordings,  with microphones replacing horns. An early example of a UK electrical recording was Handel’s Messiah conducted by Thomas Beecham.

A notable past EMI employee was Alan Blumlein. He joined The Gramophone Company in 1929 and was with them when Abbey Road Studios opened in 1931, the same year that Electrical Musical Industries (EMI) was formed from the merger of The Gramophone Company and the Columbia Gramophone Company. During his tenure with EMI this remarkable man developed moving coil microphones, a binaural cutter head and a stereo ribbon microphone. His wide-ranging stereo patent, lodged in 1931, expired in 1952 and, incredibly, it wasn’t renewed.

A stereo recording of the Royal Philharmonic Orchestra, again with Beecham as conductor, was made by EMI in 1934, while the team at the Hayes research laboratory’s stereophonic tests included recording a train passing. However, EMI didn’t consider stereo important at that time! Blumlein died during World War II while testing an airborne radar system but his microphones are still used today.

Until the early 1950s recordings were made directly to discs using a pair of ‘gravity-fed’ cutting machines driven by weights. As is well documented, when the Allies liberated Germany in 1945 they discovered the Magnetophon, a recording device using ¼” tape. Ampex in the US and EMI developed their own versions, the EMI machine being the BTR-1, which ran at 30ips. Simon noted that test recordings made on that machine still sound good today.

Stereo recording at 15ips began in 1955. A recording made of a Beecham rehearsal at Kingsway Hall in 1958 used a Vortexion mixer, EMI BTR-2 and Reslo microphones. The reason? All other mics were in use at the time!

Having provided this potted history, Simon moved on to talk about restoration. Early transfers from disc at Abbey Road were made using EMI’s own (analogue) equipment which could remove some of the clicks and pops, the bigger clicks being edited out after the transfer to tape.

In the mid-80s computer technology started to be employed and is now widely used for audio restoration. Abbey Road has an extensive array of tools developed by Cambridge, UK-based Cedar Audio. This includes what Simon referred  to as “declickle”, a combination of de-click, de-crackle and broadband noise reduction. These tools have to be used with discretion, Simon noted, particularly where the human voice is concerned as it is prone to suffer if processing is over used.

Simon sees the role of a remastering engineer as being like that of a curator, re-presenting works for successive generations. He will recommend that a work is remastered from scratch where the technology has improved sufficiently to make a significant difference to the end result.

By far the biggest problem when dealing with material on analogue tape is old edits. The splices can come unstuck.  Oxide  shedding is another issue, often solved by baking the tape at 50° for three days. EMI’s tapes are not usually a problem in this respect as they are stored in a good environment at the company’s library in Hayes.

The remastering process involves finding the best source – which in itself can be a painstaking process – transferring the material to digital, treating it and editing on SADiE. Lastly, some EQ or compression may be applied, but only where appropriate. An engineer’s ears are the final arbiter, Simon noted. Knowing when to leave alone.

Equipment employed include TC Electronic’s System 6000 dynamic processor and, as mentioned earlier, restoration tools from Cedar Audio, in particular, Retouch. A full description of this remarkable system is not possible here, but suffice to say that it acts a bit like an audio version of Photoshop. The different elements within a piece of audio are represented as differently coloured visual  images and the engineer can then remove an individual element by effectively painting it out.

Simon went on to discuss a particular project which used Retouch in a rather unusual way to create the soundtrack for the Beatles’ Rock Band game title. This involved isolating various instruments and vocals to create individual tracks that those playing the game can reproduce by ‘playing’ their instruments.

Because the original Beatles recordings were made on 2-, 3- or 4-track machines, it is not possible to simply mute individual instruments or voices, as it would be today with the virtually unlimited number of tracks offered by hard disk recording systems. Each instrument or voice therefore had to be extracted on to a separate track by identifying its visual pattern on the Retouch display.

The results were impressive, but unfortunately the only way to hear them will be to play the game!

Report by Bill Foster

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