Tech Focus: Digital Audio Networks

By Dan Daley, Audio Editor, Sports Video Group

Part 1 — A Proliferating Presence in Sports Venues

Digital audio networks have become the fastest-growing category in professional audio in recent years, and they are having an impact on sports venues. Although their rapid rise has given them a patina of high-tech novelty, the idea has been around for more than two decades.

Joe Patten, an associate at Boston-area consultancy Communications Design Associates, recalls the first audio network he specified for a sports venue: a CobraNet system for the Tennessee Titans’ new and then-named Adelphia Stadium in 1999. “At the time, it was rudimentary, but it was what we had. Today, we see some kind of advanced audio networking in virtually all new stadiums and for sound-system upgrades.”

He notes that problems particular to sports venues are solved by systems like the Dante/Symetrix DSP combination platform he usually specifies: long-distance cable runs for line-level audio signals and induction issues for voltages that cause induced line noise. In addition, he says, the cost savings and efficiencies that networking brings are significant: “[They’re] measureable [given] the amount of copper cabling we used to use.”

However, Patten says, A/V systems integrators aren’t necessarily enthusiastic about networked audio, because they either aren’t familiar with the concept or have had the wrong kind of experience with it. He notes that CobraNet, the first widely used networking platform, was dogged by latency and other performance issues.

Dante’s support for redundant connections on the network won’t stop the show. Redundant primary and secondary connections can be set up in a star-network configuration so that problems in any part of the network won’t interrupt the signal flow or bring the entire network down.

Dante’s support for redundant connections on the network won’t stop the show. Redundant primary and secondary connections can be set up in a star-network configuration so that problems in any part of the network won’t interrupt the signal flow or bring the entire network down.

“CobraNet was the first kid on the block, and it served its purpose,” he says. “But it also may have put some people off of networked audio. Today, with platforms like Dante, the cost savings and efficiencies you get with networked audio vs. analog cabling are too considerable to not use it.”

Too Much Choice
If A/V integrators and consultants had too few platform choices 20 years ago, today, they may have too many, with close to a dozen protocols and standards-based platforms competing for market position. (See Tech Focus: Digital Audio Networks, Part 2.) Some of them are open standards: they allow components from various manufacturers to work on a network but have the potential for individual components to not always play well together. Others are proprietary: a closed ecosystem uses only components from a single vendor or its certified partners. The interoperability standard AES67 is intended to bridge the divide between open and proprietary, as well as proprietary and proprietary.

The most successful proprietary network so far is Audinate’s Dante, which has achieved a level of critical mass — reportedly close to 300 licensees make more than 700 compatible products, from amplifiers to mix consoles — that has prompted many observers to call it the de facto industry standard. Its presence in sports venues can likely be traced to the 2012 installation of a Dante network combined with three Symetrix SymNet Radius 12×8 processors at the Wells Fargo Center, home to the Philadelphia 76ers and the Philadelphia Flyers.

A source at Audinate estimates that there are about 40 Dante-enabled sports-venue installations globally, 15 in Europe, including Manchester City Stadium and the Regensburg Continental Arena. Most of the rest are in the U.S., including the Titans’ updated Nissan Stadium and the Pittsburgh Pirates’ PNC Park.

Many network suppliers are targeting sports venues. QSC, whose proprietary Q-Sys system is installed at Dynamo Stadium in Tbilisi, Georgia, and at the NFL Detroit Lions’ Ford Field, has a dedicated web page for sports. Yamaha, an early adopter of the Dante network, has done the same. Ravenna, championed by European audio manufacturers like Lawo, has gained significant traction at venues in Europe and the EMEA region.

Networked audio is quickly becoming the norm for sports-venue systems design and integration. According to Phil Wagner, president of Focusrite Novation, which markets the RedNet series of network interfaces installed in venues including the Dayton (OH) Dragons Minor League Baseball park and used for the halftime field sound for the Super Bowl, systems designers and integrators can’t ignore the cost savings that come from networked audio.

“Moving audio onto a fiber cable increases flexibility, because you can put microphones or speakers anywhere you can run a single cable to, and reduces cost, because you’re no longer running dozens or even hundreds of strands of copper anymore,” he explains. “And it improves the overall quality of the field audio, because the network is immune to the hums and buzzes and other artifacts of analog audio. Between Dante and AES67, the infrastructure is now here for affordable, reliable networked audio.”

Part 2 — The Major Players

Audio-networking platforms have proliferated in recent years, underscoring the shift from copper to fiber for signal transport. They offer significantly more channel counts and the virtual elimination of latency, but their diversity in types and features — not to mention the added complexity of IT-based foundations converging with the traditional A/V base of the broadcast plant, remote ops, and sports venues — makes for a complicated transition. Here’s a look at the major players in the audio-networking sector at the moment.

Click here for Tech Focus: Digital Audio Networks, Part 1 — A Proliferating Presence in Sports Venues.

A standard for audio-over-IP interoperability, AES67 was developed by the Audio Engineering Society and published in September 2013. It is a Layer-3 protocol suite based on existing standards and is designed to allow interoperability between various IP-based audio-networking systems, such as Ravenna, Q-LAN, and Dante. The Media Networking Alliance was formed in October 2014 to promote adoption of AES67.

Created by Audinate, Dante is an uncompressed, multichannel digital media-networking technology, with near-zero latency and synchronization. The company passed the 200-licensee mark this year.

Owned by Cirrus Logic, CobraNet is a combination of software, hardware, and network protocols designed to deliver uncompressed, multichannel, low-latency digital audio over a standard Ethernet network. Developed in the 1990s, it is widely regarded as the first commercially successful implementation of audio over Ethernet. It was designed for and is primarily used in large commercial audio installations, such as convention centers, stadiums, airports, theme parks, and concert halls.

Digigram’s EtherSound is compliant with IEEE 802.3 Ethernet standards and has been developed as both ES-100 (for use on dedicated 100-Mb Ethernet networks or within a Gigabit network as a VLAN) and ES-Giga (for use on dedicated Gigabit Ethernet networks).

Livewire+ is an audio-over-Ethernet system developed by Axia Audio, the studio-audio division of Telos Systems. Introduced in 2003, Livewire+ is designed primarily for radio stations’ routing and distribution of broadcast-quality audio. Livewire is interoperable with Ravenna standards-based systems and equipment. The most recent iteration of the protocol enables full AES67 interoperability. Designed as a superset of functionality using common protocols and formats, Livewire+ is available as an open standard through Axia’s Livewire+ Partner Program. To date, there are more than 80 Livewire+ partner companies. As of 2015, Livewire+ was installed in more than 6,000 studios worldwide, and more than 60,000 individual Livewire+ devices were in the field.

A proprietary digital audio and video network, Optocore is designed to carry 1,024 inputs to any output of all network nodes at the lowest fixed latency (41.6 μs is currently achievable).

QSC’s software-based DSP platform, Q-SYS provides a Layer-3 network-audio protocol natively on the same Intel hardware with no additional cards or hardware required. Q-LAN, QSC’s network-audio protocol, also provides device discovery and conveys control and monitoring to and from system peripherals. The Q-SYS Platform comprises the Core 3100, Core 1100, Core 500i, and Core 250i hardware and, combined with Q-SYS Designer Software and peripherals, makes up the complete platform.

Using standard network protocols and technologies, ALC NetworX’s Ravenna can operate on most existing network infrastructures. The format has primarily targeted the professional-broadcast market, including in-house signal distribution for broadcast plants and other fixed installations, interfaces at venues and live events, outside-broadcasting support, and inter-studio links across WAN links and production facilities. Ravenna has its biggest traction in the European markets.

Riedel’s RockNet real-time, low-latency audio-distribution network conveys 160 24-bit/48-kHz audio channels counterrotating on a single Cat 5 cable. The system can accommodate up to 99 devices on a single network.

Based on Internet Protocol, Wheatstone’s WheatNet-IP network system enables audio to be intelligently distributed to devices across scalable networks. It enables all audio sources to be available to all devices (mixing consoles, control surfaces, software controllers, automation devices) and to be controlled from any and all devices. WheatNet-IP is AES67-compatible and represents an entire end-to-end solution, complete with audio transport, full control, and a toolset to enable exceptionally intelligent deployment and operation.

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