With no shortage of announcements during the recent ISE 2014 trade show, the audio networking bandwagon evinces no sign of slowing down. But is the apparent objective of true interoperability in sight now, asks David Davies?

“We are very proud of Extreme Networks’ dedication to furthering the momentum of AVB and of all our members working together toward a true ecosystem of AVnu-certified devices,’ says Rick Kreifeldt, chairman and president, AVnu Alliance.
On 25 August this year, the AVnu Alliance – the organisation created to support and promote the AVB (Audio/Video Bridging) networking standards – will celebrate its fifth birthday. There is no doubt that it is a landmark anniversary – and not just for what it says about progress towards a universal approach to audio networking.
At the most basic level, and to its credit, the Alliance has prompted an unprecedented amount of collaboration within and beyond the AV and IT industries.

From a founding quintet of companies including Harman, the Alliance has grown to a current membership of 65, with residential systems specialist Crestron the latest to climb aboard, in January this year. Biamp, Dolby, Focusrite, Meyer Sound and Sennheiser are among a very considerable pro-audio contingent participating in the project – and the level of uptake in what had historically been a distinctly protectionist sector has certainly taken some by surprise (as one notable industry figure remarked to me at the time of the Alliance’s launch:, “We don’t really tend to do collaboration in this industry!’)

But perhaps even more importantly, the group’s creation confirmed a significant, if at times painfully slow-dawning realisation, within the audio industry that a networking future based around closed protocols was likely to be an extremely limited (and limiting) prospect. Speaking at the SVG Europe Sport Facility Integration Summit, held during this year’s ISE, Rick Kreifeldt – chairman and president of the AVnu Alliance as well as being VP research and innovation of Harman International’s Corporate Technology Group – recalled that the industry’s inward-looking approach had at times left it: “stuck in a wheel of doom.’

With the AES among the other industry organisations to have spearheaded standards-backed interoperability efforts, the last half-decade has – if nothing else – confirmed that Kreifeldt’s believe in unified solutions is now pretty much universal. Powerful networks, runs the philosophy, boost efficiency and allow installations or live/broadcast deployments to be scaled in size with maximum ease and flexibility. But how close are we really to that Edenic land in which devices from multiple manufacturers can be brought onto the same network with guaranteed interoperability?

A brief history

If one is tempted to date the beginning of the latest “phase’ of networking to the creation of the AVnu Alliance, the truth is that concerted moves in the direction of seamless digital networking really began in the mid “90s. Arguably the most significant technology to emerge at this point was CobraNet, developed in 1996 by US-based Peak Audio but subsequently acquired by Cirrus Logic.

Without doubt the first properly commercially successful implementation of Audio over Ethernet, CobraNet allows 64 channels of uncompressed digital audio to be carried through a single, inexpensive Cat5 cable. The technology became particularly popular in the “fixed’ install markets of convention centres, stadiums, airports and theme parks.

Although it remains widely used today, hardware costs and a latency issue (delays of 11⁄3 milliseconds per network traversal meant it was impractical for some applications) meant that CobraNet was unlikely ever to be an all-purpose panacea. So the development of other technologies continued apace, with Harman’s HiQnet and QSC’s QSys among the solutions to garner credible market traction.

But an abundance of options hardly helped to sway those who were firmly not of the early adopter persuasion to consider moving away from simple point-to-point connectivity. Simultaneously, an increase in the expectations of what AV networks might be able to deliver in terms of traffic and complexity meant that more decisive action had to be taken if full networking was to achieve a meaningful breakthrough.

Towards interoperability

It was to be several more years before, in the mid-noughties, the emergence of new IEEE standards suggested that a useful point of congruence might be in prospect. Beginning to take shape in 2005 but not completed until August 2013, the group of standards that came to be known as Audio/Video Bridging (AVB) provided the specifications to allow time-synchronised low latency streaming services through IEEE 802 (typically Ethernet) networks.

By 2009 a group of companies from the audio, video, broadcast and IT communities were sufficiently convinced by the technology’s possibilities to create the AVnu Alliance to promote the adoption of the related standards – and, equally crucially – ferment a certification programme that would guarantee the interoperability of devices sitting on AVB networks.

After several years in development, the certification programme finally got underway in early 2013 and delivered its first AVnu-certified products – the Extreme Networks Summit X440 AVB switch series – in time for this year’s ISE show. With the aforementioned announcement about Crestron to flag up at the Amsterdam gathering, Kreifeldt was upbeat, describing the past year as an “extremely productive period’ for AVB.

Referring to the Extreme Networks switch series as the first of many AVnu-certified products in the pipeline, Kreifeldt says that “we have also (been) actively developing programmes for wireless audio, audio over IP and automotive, with pro video to come in 2014. We are very proud of Extreme Networks’ dedication to furthering the momentum of AVB and of all our members working together toward a true ecosystem of AVnu-certified devices.’

But the reality is that – led by the likes of influential audio consultant Roland Hemming – the AVB movement has lately been the subject of increased debate and even dissent. “It seems to have taken an extraordinary length of time (to get a product through certification),’ says Hemming. “I’d also argue their approach to promoting the technology has been poor and that (the AVB camp) hasn’t really engaged with the market sufficiently.’

And notwithstanding the Extreme Networks switch development, Hemming remains concerned about the availability of the dedicated switches required to make AVB networks run. Such switches, he says, are limited in number at this time and are: “more costly to purchase than comparable non-AVB-enabled switches.’ The reality check, he adds, is that: “the audio gear simply isn’t there.’

Not surprisingly, Kreifeldt is inclined to offer a rather more positive spin on the current AVB product landscape. “Most of the pro AV manufacturers (in AVnu) are designing products with AVB included or have AVB-enabled products already shipping,’ he says. “Some notable examples are from many of the members that exhibited in the AVnu Alliance Pavilion at ISE 2014; including the Tesira Family from Biamp; Extreme Networks’ multiple switches; Harman’s 64×64 BSS Audio Soundweb London processor; Riedel’s Artist digital matrix intercom platform; Meyer Sound’s CAL column array loudspeaker and D-Mitri digital audio platform; Avid S3L live sound system and Avid Pro Tools 11; and Yamaha’s CL 1 console with 64 channel talker/listener.’

AES67 arrives

As Hemming notes, Layer 2-oriented AVB can create: “A significant hurdle for some applications, not least those where there is a requirement to route across subnets.’ Momentum behind approaches geared towards Layer 3 transport can therefore assume a higher profile of late.

Dante is increasingly a “go to’ technology for demanding network applications. In the words of its developer, Audinate, Dante delivers a: “no-hassle, self-configuring, true plug-and-play digital audio network’…that uses standard IP over 100Mb and/or Gigabit Ethernet. Dante technology can distribute digital audio plus integrated control data with, notes Audinate: “Sub-millisecond latency, sample-accurate playback synchronisation, extreme reliability and high channel counts.’

Audinate announced its 100th Dante OEM partner in September 2013 – since when Glensound and Digital Labs, among others, have joined the fray. “Not only are we the market leader in live and commercial live and commercial audio, we are seeing the same phenomenon in broadcast networks and public address and evacuation systems,’ says Audinate CEO Lee Ellison. “Audinate has made it very easy with our developer tools to integrate into our OEM products so they do not need to spend multiple years in development.’

Then there is the Ravenna technology developed by ALC NetworX, which again uses standard network protocols and technologies. Providing real-time distribution of audio and other media content, Ravenna can operate in existing network infrastructures – a feature that has seen it enjoy particularly enthusiastic take-off in the broadcast world, as evinced by the technology’s year-on-year profile increase at IBC.

The latest news pertaining to Ravenna includes the announcement, late last year, of a ’deeper collaboration” between ALC NetworX and Digigram that will allow the full Digigram product line to be powered by Ravenna for real-time IP-based distribution of audio and other media content.

With a partner list that includes Genelec, Merging, Neumann, Schoeps and Sonifex, Ravenna – like Dante – has already garnered a robust market profile. But in this new era where integrators increasingly seek reinforcement by standards, both solutions look set to benefit from the arrival of AES67. Developed by the Audio Engineering Society and published last September, AES67 is a Layer 3 protocol suite designed to allow interoperability between various existing IP-based audio networking systems.

Andreas Hildebrand, senior product manager at ALC NetworX, explains the meeting place-style role that can be played by AES67: “Audio over IP technologies, including Ravenna, was in existence for quite some time, but although featuring some commonalities, they were not able to interoperate with each other. The motivation for AES67, then, was to define interoperability guidelines to which existing solutions can be adapted with reasonable effort to facilitate synchronised inter-system stream exchange. It is important to note that AES767 is not intended to be a solution on its own, but rather (provides) means for exchanging audio streams between areas with different networking solutions or technologies already in place.’

Indicating its likely importance, ISE was frankly awash with AES67-related announcements. Through the formal incorporation of the standard via a firmware update to be released to OEMs within 12 months, Dante will add a Layer 3 RTP (Real-Time Transport Protocol) option to its existing Layer 3 UDP (User Datagram Protocol) transport. ALC NetworX, meanwhile, highlighted the fact that Ravenna is already AES67-compliant.

The extent to which AES67 might provide a unifying path for audio networking will be explored in greater depth in next issue’s follow-up feature in Pro Systems News. But whatever the standard’s potential, casual conversations with integrators at ISE 2014 underlined the high level of continuing confusion about the pros and cons of different approaches to networking. Whether to invest and in which solution to invest their faith are abiding questions. The commercially-sensitive nature of many of these developments can understandably limit the spread of information, but a more joined-up philosophy with regards to industry education is surely essential if comprehensive networking is to become the norm.