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Raising the Bar For Reproduction

Los Angeles, CA—At the end of 2011, the AES announced the formation of a provisional committee to review audio reproduction for digital cinema and television with the intention of eventually arriving at a standard that addresses some of the current issues.

Los Angeles, CA—At the end of 2011, the AES announced the formation of a provisional committee to review audio reproduction for digital cinema and television with the intention of eventually arriving at a standard that addresses some of the current issues. The committee is expected to shortly begin formulating a framework for audio improvements.

“The current digital cinema audio system is simply not the best we can do,” states Brian McCarty, who is leading the committee with engineering guidance being provided by Dr. Floyd Toole, vice chair of what is known as the Audio Engineering Society Technical Committee on Sound for Digital Cinema & Television (or AESTC-SDCTV). McCarty is a former Hollywood sound technician who is now managing director of Coral Sea Studios in Australia.

McCarty previously noted, in a statement released along with the announcement of the formation of the new committee, “In simple terms, what is recorded digitally in the studio does not sound the same at the theatrical end. Acoustical design of theaters is typically incorrect for sound reproduction in large rooms. Current soundtrack EQ reproduction curves are inconsistent with largeroom audio practice and, with the rest of the audio industry. And, loudspeaker technology typically used in theaters has yet to be optimized for proper playback of wide bandwidth soundtracks.”

The format deserves careful study, according to comments by Toole in the same statement: “It seems that no real science has been done in terms of digital cinema sound.”

Digital cinema sound issues were originally addressed in 2010 at AES Technical Committee meetings in London. Now, in order to address the apparent lack of electroacoustical response reference data for digital cinema systems and establish a framework for its improvement, Mc- Carty and Toole will be contacting key personnel from the film audio community.

“We’ll see if we can’t all agree on a common understanding about what’s wrong,” says McCarty. “At the AES in Budapest in April, we’ll have a plan for working groups to attack the different elements of this.” Some big names have already signed up to the committee, he adds: “I’m really heartened that there’s this much high-level interest.”

Digital Cinema Initiatives, a joint venture of the major Hollywood studios, released voluntary specifications for an open architecture for digital cinema in 2008 that set an audio standard of 24-bits at 48 kHz or 96 kHz with a maximum 16 channels. The AES, which has some historical involvement with film sound, could ultimately unify audio standards across multiple disciplines.

In the meantime, a panel of representatives from Barco, Dolby Laboratories and Sony Pictures Entertainment will report on the latest cinema sound advances from the Society of Motion Picture and Television Engineers (SMPTE) at the NAB Show in April. The session is scheduled to provide an update on the progress of the SMPTE B-Chain Study Group, focusing on acoustical measurement techniques for improved interchange and interoperability for the cinema, a novel approach on packaging and playback of audio tracks for 3D and a presentation on audio processing for cinema applications

According to McCarty, many exhibitors initially saw the transition to digital projection in their theaters as an opportunity to make ancillary revenue, in particular from live simulcast concert events. But as McCarty reports, comment cards turned in by the audience at these events have typically rated the picture quality highly but the sound only poorly. “We ought to be able to put a concert-level signal in a 5.1 format into a movie theater and have it sound like a concert. We’ve degraded the signal so much to match what’s going on in the theaters that it’s a subset of audio now—it’s movie sound.”

A description of the formative AESTC-SDCTV states, “The Technical Committee will study current audio reproduction standards for Digital Cinema and Television, which may benefit from revision in the light of current knowledge, reproduction systems and listeningspace acoustics. There is also a need to establish better compatibility with television distribution methods including Blu-ray and 3D Television, and to attempt to unify the approaches to reproducing music and cinema/TV sound. In the past, audio reproduction for cinema and TV was treated somewhat differently to other types of reproduction. However, it is possible that these differences no longer apply so clearly, and there is a motivation to integrate multiple types of audio reproduction under common standards.”

“The AES is starting from the premise that we know something is wrong, let’s fix it,” says McCarty. “Our mission is to identify a consistent approach to controlling perceived loudness and frequency response from installation to installation, and from position to position within digital cinema installations worldwide and for this to be adopted as the formal reference for all contemporary dubbing stage recording and mixing activities, and ultimately as the unified method for film reproduction at home.”

Audio Engineering Society

Society of Motion Picture and Television