The History and Future of Surround Sound

Tomlinson Holman presented to our Section in the face of significant upheaval caused by an upset to his travel plans. In San Francisco, unable to fly home due to fog, he presented from a hotel room there (“always have a backup plan”).

Image of the presenter, Tomlinson Holman presenting via Zoom — *Tomlinson Holman presenting via Zoom*

After a brief introduction from Section Chair Graeme Huon, Tomlinson commenced his presentation, which he had titled “The History and Future of Surround Sound: A Story of Death and Resurrection in Six Acts”. He started by playing a recording of “The Flight of the Bumblebee” as an Overture, commenting that this tune was selected for a reason – a choice that will be explained later – stay tuned.

Tomlinson described the journey of surround sound, starting well before the days of microphones and loudspeakers, taking us back to the 1500’s, where the spatial perception was created within reverberant churches by judicious placement of chroisters, starting with a simple left/right orientation and moving on to more immersive configurations, culminating in 1714 with 4 organs at Freiburg Cathedral, one positioned high (“swallow’s nest”) and creating a “surround sound” effect. He described how, by the 19^th Century, as composers stretched the envelope, it was orchestras which were being replicated (x4) and positioned at the four compass points. Music was being composed to take advantage of the surround effect this provided.

He then moved into the 20^th century, where the advent of microphones, electronics, and loudspeakers opened the possibilities far wider. Tomlinson spoke of Bell Labs’ experiments with stereo in 1933, with the live transmission of an orchestra from the Academy of Music in Philadelphia to Constitution Hall in Washington, DC. He then spoke of Snow’s “thought experiment” into ways to capture and transmit the full concert experience, proposing an infinite number of microphones on the performance stage, feeding an infinite number of loudspeakers via an infinite number of transmission channels. Tomlinson commented that, for practical reasons, this infinite number was reduced to just three (Left, Centre, and Right), relying on the receiving hall’s acoustics to create the “enveloping” sound.

He spoke of “crossover” conductor Leopold Stokowski’s involvement in the Bell Labs’ experiment and his ultimate involvement with Walt Disney’s ground-breaking Fantasia. Tomlinson listed the achievements and inventions needed to realise Fantasound – adding surrounds to the basic L,C,R, the panpot, recording to a click track, overdubbing, and distributed surround speakers.

He explained that the surround audio format was originally conceived to be able to track the bee in “The Flight of the Bumblebee”, but ironically, that piece ended up on the cutting room floor, but the surround stayed. Hence, the Overture chosen.

Slide of the Cinemascope audio carried by magnetic stripes on the print.

Tomlinson then moved through the many different film formats that quickly followed, and the sound configurations needed to support them – Cinerama, Cinemascope, Todd-AO and Panavision.

He then briefly covered the shift in the fifties from the shrinking theatre market to the new home stereo market, where the move from three (front) channels to two, created a phantom (rather than “hard”) centre channel. Then the ill-fated Quad format was touched on lightly.

In his “Act IV” which Tomlinson titled “Resurrection – where our hero comes to stay” he covered the 1977 release of Star Wars using Dolby Stereo.
He credited it with bringing surround sound to the masses. Then, with the 1979 release of Superman and Apocalypse Now on 70mm, with added stereo surrounds and a “baby boom” channel, he suggested that 5.1 had arrived, but the name had to wait until 1987.

Tomlinson related how he participated in SMPTE’s 1987 discussions on Digital Sound on Film, where, as well as sample rate and bit depth, the number of channels had to be decided. Options canvassed were 2 channels (LtRt matrix encoded), 4 (L,C,R,S discrete), 8 (L,LC,C,RC,R,LS,RS,Boom discrete) – but Tomlinson said 5.1 – what? L,C,R,LS,RS,LFE. He explained that the actual engineering number was 5.005 for the bandwidths of the main and LFE channels, but that 5.1 was “marketing rounding.”

History was made.

Slide of the 70mm print showing the four competing audio formats DTS, Analog LtRt, Dolby Digital, and SDDS.

Tomlinson then covered the formats that followed and expanded on this, like Dolby SR-D (1992), DTS (1993), and Sony SDDS (1993). He explained how each of these could co-exist on a single print, with Dolby SR-D encoded between the perforations, DTS time code for CD-ROM follower inside the analog soundtrack, and SDDS on both sides of the perforations.

He went on to cover the home DVD boom, which saw 5.1 sound entering the home, commenting that the rapid rise in income from DVD (and later Blu-ray) sales saw the movie studios and producers now regarding the theatrical release as a trailer for DVD sales. He noted that this has been shrinking over time with the rise of streaming delivery.

He lamented that with the advent of large screen flat panel televisions, the popularity of home theatre systems has waned, and people are suffering with sound from one-inch loudspeakers or poor quality soundbars.

Tomlinson then re-examined 5.1 to see what it did well and what it did poorly. He gave front imaging and surround envelopment a “tick”, but graded side imaging and overall sound imaging all round as “poor”. He suggested that the addition of a Back Surround would improve matters significantly, as would addition of “wide” channels adding to the source width, envelopment, and imaging-all-round. He also suggested that the addition of a pair of “height” channels (in front +/-45º, in plan 45º) and stereo sub-woofers would be beneficial. Tomlinson proposed an upgrade from 5.1 to 10.2.

Tomlinson then covered Object Immersive Audio, the best-known example of this being Dolby Atmos, and then binaural audio. He commented that measuring in-ear-canal response of a system and reproducing it electronically with head tracking works, and noted that Covid brought this technology back to mixers’ attention. He cited some major mixers who now may mix at home on headphones.

Photos of the Apple Vision Pro headset which uses Apple Spatial Audio

This technology led us to Tomlinson’s recent work with Apple, leading the spatial sound team for the Apple Vision Pro, citing all the positive reviews of the spatial audio in this headset.

The presentation concluded with a Q&A session covering a range of topics, including a question about the future of surround continuing to be incremental improvements or could there be a revolutionary jump. Tomlinson’s answer indicated that he believed that there had been revolutionary steps in the past, citing Fantasia, but that most improvements to date had been evolutionary. He indicated that there was room for more revolutionary changes, but that the loss of mainstream popularity of home theatres with the large-screen flat panel displays did reduce the opportunities for major advancement. He proposed that with increasing channel bandwidth lots of channels could be delivered to the end user but then be deployed variably depending on needs depending on accompanying metadata to switch, for example, between best seat in the house vs. best seat in the middle of the band.

Other topics discussed included the future of ambisonics, audio for games and virtual reality, the problem of home video/streaming mixes unsuitably limited for high-quality home theatre systems, and Atmos downmixes to stereo for headphones.

We thank Tomlinson for a most interesting and informative evening, particularly in light of his travel complications.

The History and Future of Surround Sound

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