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Blu-ray Disc: saviour of surround sound without pictures?

History shows that audio-only surround-sound formats often come to grief, but another contender has stepped into the ring. Kevin Hilton finds out more.

The course of audio-only surround sound has never run smoothly. Quad personifies the overblown 1970s and although Ambisonics and holophonics are clever technologies they remain specialised techniques. DVD-Audio is now presumed extinct and while SACD (Super Audio compact disc) has outlived its one-time rival, it is a niche product.

Despite this, German authoring, post-production and mastering house MSM Studios believes there is a market for surround without pictures and that Blu-ray Disc (BD) is the right medium for the job. Pure Audio Blu-ray was developed by the Munich-based facility during 2008, with the first title in the new format released the same year.

MSM Studios is now waiting for confirmation that its audio-only BD system will become an AES standard later this year. A small catalogue of Pure BDs has been compiled over the past two years, with titles ranging in style from Grieg (pictured) and Mozart through audiophile singer-songwriter-guitarist Sara K to world music artist Jienat.

Established in 1991 as a CD mastering house MSM Studios expanded over the years into DVD-Video, with some forays into DVD-Audio and SACD. When BD appeared, managing director Stefan Bock realised the format had capacity for high-resolution audio and that there was nothing on the market to exploit this.

“We saw that BD was a great format and asked ourselves why no one was using it for audio,” he comments. “Then some of our customers started asking about audio-only and why no companies were dealing with it. So we began to think that maybe this was our chance to produce an audio format based on BD, using our in-house Java coding experience.”

Bock says he and his team looked at what lessons SACD and DVD-A had for anyone considering another high-resolution audio-only surround format. Both systems were hindered by relying on the willingness of consumers to buy special players, which led to the conclusion that the audio market on its own was not big enough to sustain and support its own high-definition/resolution sound system.

Changes in how the music business works made Bock more confident that creating a specialised format on an open platform would be possible. “The times are gone when the record industry has enough power to set standards for play-back,” he says. “People want a universal device and BD provides that because it will play CDs, video DVDs and audio-only Blu-rays, as well as its own HD video discs.”

Four years ago the big manufacturers and record companies were still actively supporting SACD and, to a lesser extent, DVD-A. That situation has changed dramatically since then. Jim Bottoms, a director of media research company Futuresource Consulting, comments that DVD-A is “pretty much dead”, while SACD is a small market, with only a few releases aimed at the “esoteric high-end”. Bottoms adds that while surveys show people are open to surround sound without pictures there is not a great demand, with DVD-Video music releases in 5.1 showing only “minor flurries” in sales.

What this means for Pure Audio BD is not clear. “The key now is whether a format is compatible with existing players,” Bottoms says, “so people don’t have to buy new hardware. But Pure Audio BD will also have to be adopted by the record companies. That might happen with some classical labels but there are independent companies out there that are struggling with BD in general because of the cost of production and the expense of getting shelf space in shops.”

Bock agrees that producing a video BD is “quite costly” because of the amount of coding involved, but says the aim was to have cost-effective or at least similar production outlay for audio-only discs.

The Java code for Pure Audio BD was written within the constraints of the Blu-ray specification, which did not include an audio-only component. The surround-sound format used by MSM Studios is DTS and DTS HD, which are already part of the BD spec.

Bock says an important aspect of Pure Audio BD is the navigation, which works like a conventional CD machine and allows music to be played without having the TV screen on all the time. “If something is too complicated people won’t use it,” he observes.

Pure Audio BD was submitted to the AES for consideration as a standard in October 2009. A spokesman for AES Standards says the application is going through the usual procedure and reaction had been “generally positive”, with no contrary voices heard so far. A final decision will be announced around the time of AES London in May. If successful, Pure Audio Blu-ray will become AES standard X-188.

MSM Studios is the only facility producing Pure Audio BDs right now but an authoring kit is available for other mastering houses. An online service has also been created to advise outside engineers on how to create audio-only recordings. Bock says that this could help the format in general: “Other facilities won’t have to spend time with the Java code and more people might want to use Pure Audio BD, which we need because there has to be a wider range of titles if this is going to be viable for the consumer.”