Audio Networking: Broadcast Sound on the Move, Part 1

Digital-audio networking is audio’s newest frontier, and, although the concept of packetizing digital audio over a data network has been around for some time, it has been making its presence felt more strongly in the past year or so. New broadcast facilities in plants and in sports venues and the live-sound infrastructure of the venues themselves are increasingly being fitted with a growing assortment of networked-audio solutions.

Dedicated LANs and WANs are used to move audio as data packets around a facility, a venue, or the world, and networked audio was abundantly used at the recent Sochi Olympics. Networking increases signal-transport capacity and throughput, a critical improvement with channel counts for live sports shows increasing. It has become especially useful as sports events take place on larger sites, such as last year’s Red Bull AMA Amateur National MX Championship and the Traxxas Off-Road Championship, where a Riedel RockNet network was deployed.

Two decades ago, there were two main options for networking audio: CobraNet, developed by IT company Cirrus Logic in 1996, and EtherSound, a France-based system that came to market five years later. Both created the foundation for what has become an extensive landscape of network solutions today. Both are still in use, most heavily in Europe, although they have been somewhat eclipsed by subsequent developments in terms of speed and features. For instance, CobraNet’s latency is in excess of one second, acceptable for some types of live-sound applications but nowhere near the millisecond values required by broadcast.

What has come in their wake is a variety of proprietary systems, open-source approaches, and standards-based protocols offering more capability and speed. These include Dante, Q-Lan, Optocore, Ravenna, WheatNet, and others. However, like any rapidly expanding technology sector, they also come with different feature sets, various degrees of compatibility with other systems and products, and a noisy wall of competing marketing campaigns.

Proprietary vs. Open
Proprietary approaches trumpet their individual advantages but, in some cases, actively try to become compatible with other networkable audio products. Most notable among these is Dante, from Australia-based Audinate, which now lists more than 85 licensed partners and has achieved the best traction in the U.S. market, including in sports venues.

On the other hand, open-source advocates also underline interconnectivity. Audio/Video Bridging (AVB), a technology represented by the AVnu Alliance, a non-profit consortium of more than 60 members (including putative competitors, such as the manufacturers of Dante and RockNet), has been slow to reach the market, a condition of its having to adhere to stringent IEEE standards of development and testing, proponents assert. But, they add, it will offer the widest range of compatibility, given the depth of its partner members, which range from hardcore IT entities like Cisco and Intel to consumer brands like General Motors and BMW. The AVnu Alliance certification program is now under way, and all members are eligible to have their products certified by an AVnu Alliance-approved test lab.

Clear Benefits
Regardless of which products or approaches are used, the benefits of digital-audio networking are clear, both users and systems manufacturers say. These include no transmission loss in transport, keeping the audio digital from input to output, negligible crosstalk, and, most meaningful to many, an increasingly plug-and-play modality with far less cabling infrastructure. Usable distances have also increased, from up to 500 ft. over Cat 5e cable to nearly a mile on multimode fiber to several kilometers over single-mode fiber.

“More signals are available by the click of a mouse or the push of a button,” says Sascha Kneider, head of technical services, North America, for Riedel, manufacturer of the RockNet platform. “Nobody needs to run additional cables to get more signals from or to a certain location. In the worst case, another [I/O] box has to be added. Last-minute changes — one more truck or recording device — are integrated within a couple of minutes. For instance, one truck could use the output signal of another truck as a submix [with] already equalized and processed signals rather than the original microphone signals. Those changes in the signal flow would not even require any changes to the physical layout of the system and, therefore, [would need] a significantly lower amount of manpower.” The bottom line, he adds: “Better quality and more possibilities for a lower price.”

Dante’s Fans
Dante has been aggressive in its marketing, and that combined with its growing number of licensees have given it a strong headstart in the sports-venue market. An example is found at the AAA Dayton (Ohio) Dragons’ Fifth Third Field, where the video-control room was recently upgraded to include two Dante-enabled Soundcraft Si Expression 3 digital mix consoles, several Focusrite RedNet network interfaces, and a Sound Devices Pix 260i DDR with Dante card.

“Dante is the next evolution of IP-based audio,” says Jamin Johnson, manager of integration and engineering at Alpha Video, the AV integrator that worked on that project. “In audio-focused environments, Dante technology is now being offered by a number of manufacturers. [In the past], we have typically been utilizing MADI to exchange multichannel audio between routers, mixing consoles, and intercom systems. We are closely monitoring the major broadcast-video manufacturers for Dante offerings, especially to complement video routers, without requiring a bridge. In future production environments, it would not be surprising to see Dante replace the traditional audio router.”

Keiran Walsh, Audinate’s UK-based senior technical solutions manager, says the rich AV-media environment in U.S. major-league venues, such as the NFL’s and NBA’s, were an opportunity for Dante, given its extremely low-latency and high-accuracy network synchronization standards. And, he adds, it also works well on the broadcast side of that equation, offering the high channel counts and the redundancy that broadcasters want. Strategically, the company also has targeted categories and partners that put it squarely in the broadcast realm, including audio consoles (Soundcraft, Calrec, Stagetec), amplifiers (Crest, Labruppen, QSC), PA speakers (EAW, Nexo), and intercomms, a sector that Walsh says is becoming critically important. He notes that RTS has incorporated a Dante card for its systems.

“If you’re in [remote broadcasting], most of the job is getting comms working,” he says. “Comms are what drives this, and Dante is uncompressed, music-grade audio that can put comms and IFB to a presenter on the same infrastructure, which makes setup faster.”

Not all intercom suppliers see the recent expansion of proprietary networking systems as a bandwagon they need to jump on, however; some have been offering their own VoIP-based signal transport for some time.

Vinnie Macri, product marketing manager, Clear-Com, notes that his company has had that capability available for a decade. “Not only can we build infrastructure for hard and soft intercom clients on IP via LAN, WAN, and Internet, but we can connect user panels and digital partyline via IP cellular via MiFi,” he says. “There are many ways to build infrastructure to accommodate comms, and well-managed IP networks are simply one solution and highly dependent on the user’s application.”

Remote-truck builders and users seem to be quite satisfied with MADI for audio-signal transport for now. “[Digital-audio networking is] not in our world yet,” says Game Creek Video VP of Engineering Paul Bonar. “I think a network or IP-based infrastructure is next, [but] it’s just not there yet for us.”

Networking is likely the way forward for transport of audio, video, and data signals. Although a market hierarchy of product solutions is emerging, what’s clear is that the industry can support diversity. That’s a good thing, because it looks there’ll be lots of choose from.