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The growing pains of surround sound

Tim Carroll has built a career on surround sound but he acknowledges that 5.1 is still in "the vast minority" on today's home entertainment scene. Kevin Hilton listens as the founder Linear Acoustic sounds off about the benefits of 5.1 but how stereo still has a place.

Even the most ardent technologist or gadget geek has to eventually bow to the practicalities of real life. Tim Carroll has been heavily involved in the development of multichannel and surround sound systems from his days as product manager with Dolby Labs’ Professional Audio Division right up to today as president and chief executive of Linear Acoustic, but he acknowledges that the majority of people either don’t have the chance – or the space – to run a full 5.1 system or have no idea how one should be set up. “I’ve found that 5.1 replay is in the vast minority – it’s mostly among bachelors because once you’ve got a family there isn’t the room or the time to arrange all the loudspeakers and the other equipment,” he says. “Correct 5.1 replay is even less common. I cannot tell you how many times I have visited homes where the 5.1 speakers are stacked up at the front all together. What’s the idea of that, a wall of surround?” Regardless of the technological ineptitude of some consumers, Carroll feels that broadcasters and product developers are often complacent in believing that everyone is watching and listening on big, traditionally designed systems. “AV consumption is changing rapidly and delivery is struggling to keep up,” he comments. “We’re seeing iPads and laptops being used as well as TVs – and even with TV very often the 5.1 isn’t turned on. The shift is towards smaller and more flexible ways of viewing and listening, rather than bigger and more complicated.” During his time with Dolby, Carroll saw the move from matrixed surround in the early ’90s back to discrete channel audio, working on Dolby Digital (AC-3), Dolby E and metadata. Since founding Linear Acoustic he has concentrated on multichannel processing, distribution, loudness control and upmixing systems for digital TV broadcasting. Computer and data-based technology has both dramatically increased the scope of what systems can do and reduced how much they cost, something Carroll views as critical for the future. “It seems that the most cost-effective and flexible methods will win,” he says. “The music industry – what’s left of it – has shown that quality is not such an issue today. Downloading is not just about being free, it’s about being fast, and video is heading the same way. What we have to think about is how to advance but maintain quality at the same time.” Part of this conundrum is how to get large amounts of HD video to mobile and other wireless devices. While not everything being “broadcast” is in 5.1 even today, Carroll says it is still the most reliable way to get material to the consumer. “It’s hard to monkey with,” he explains. “But if stereo is sent as two-channels a matrix-style AV receiver (AVR) will default to try to fill all the channels and turn it into 5.1.” Despite his belief in multichannel audio, Carroll does not see the sense of anything more than 5.1 or 7.1. “22.2?” he says. “They’re out of their minds.” But he acknowledges that stereo still “rules the roost” and is still growing, although it’s shrinking at the same time. “If you don’t have time to for a good 5.1 mix then do a spectacular stereo mix and then use upmixing,” he advises.” Carroll regards upmixing as a necessary part of broadcast production today and for the foreseeable future, although, he says, the situation will eventually turn around. “Upmixing will help in making a great stereo mix but it’s better to have a carefully designed mix than something half-assed,” he comments. “The differences between a full 5.1 mix and an upmix are not that great, it’s just that true 5.1 is a little more discrete and coherent. In years to come stereo will be a downmix of 5.1.” During NAB Linear Acoustic introduced upgraded versions of the audio/loudness manager and the LQ-1000 loudness quality monitor. Despite being heavily involved with loudness through the work of the ATSC (Advanced Television Systems Committee) in the US and the EBU in Europe, Carroll has declared himself bored with the subject, although he says this is largely through hearing himself speak about it. “The tools to get this right exist from us and others,” he concludes. “Meters are fairly common place now, there are excellent file-based techniques that allow infinite look-ahead, and now we are finally releasing content-preserving transmission processing and encoding gear. All of these systems contain the tools to manipulate content in a reversible manner to make it appropriate for small televisions, large AV systems and even portable devices. Focusing on maximising audio quality across multiple platforms is both challenging and exciting – and definitely not boring.”