Sound Connections in Audio Networking
The world of networked AV is its own kind of Babel. CobraNet, developed by Peak Audio in the mid-1990s and the first successful digital audio networking protocol, had a shot at becoming an industry standard. But while its acceptance by the pro audio industry was fast, it wasn't fast enough to outpace a host of other companies. We look at four of today's prominent protocols.
Pros: Supports standard IP over Ethernet network design, coexists with other network applications, and supports a virtual PC soundcard implementation. Dante runs on existing networks, is compatible with PCs and Macs, and offers a migration path to AVB.
Cons: Currently there's a limited number and type of products on the market, though several new OEM products are expected to be launched in 2010.
Suitable Applications: Entertainment venues, houses of worship, sports venues, live theater and music installations.
Audinate's Dante is the commercial outcome of work begun at an Australian national research laboratory. Dante uses standard IP messaging on 100-Mbps and 1-Gbps switched Ethernet networks, and allows audio, control data, and other data traffic such as e-mail to utilize the same network simultaneously. This means it can be implemented using an existing data infrastructure.
Multiple sample rates and bit depths can share the same network, and all clocks on the system are synchronized to a master clock independently of the audio data, allowing sample-accurate playback from different devices on the network. Dante uses standards similar to IEEE Ethernet Audio/Video Bridging (AVB) and is considered AVB-ready (see "Whither Ehternet AVB?" below).
Audinate's software will automatically find Dante-enabled devices on the network. Dante can carry up to 32 channels of 96-kHz/24-bit audio or 96 channels of 44.1-kHz/16-bit audio on a 100-Mbps network with a latency of 1 millisecond; a gigabit link can carry at least 10 times as many channels.
"Dante solves all problems from the most latency-critical to high-channel-count, far-flung monstrosities, [and offers] plug-and-play features including automatic address assignment and routing configuration by name instead of by number," says Gross. "But I don't think we've seen enough Dante products and installations to know whether Audinate will deliver all of this."
Lee Minich of Lab X Technologies, a Rochester, N.Y.-based engineering design firm that specializes in digital audio connectivity, likes the fact that the system offers a mechanism for discovering and connecting to Dante devices. "It also lets users affix 'friendly' names to devices rather than arbitrary alpha-numeric designations," he says. However, he adds, "Per-channel royalties make Dante products more expensive, and its functionality is most similar to AVB."
Audinate itself, however, is quick to point out the differences between its technology and AVB. "Dante's features [automatic address assignment, routing configuration, name-based configuration management, plug-and-play service discovery; along with redundancy, control, and performance monitoring] are part of the overall solution and are not included in the AVB standard," says Ashesh Doshi, director of marketing. "These features will build on AVB, which presently covers synchronization and [quality of service] resource reservation, plus transport in the near future."
Scott Ferguson, systems integration specialist at Peavey, which was an early partner with Audinate, expresses the relationship between Dante and AVB more directly: "Dante will work with any standard network switch; AVB requires an AVB compliant switch, adding cost to an AV install."
Integrator CTS Audio used Audinate's Dante system at the Oakwood University Church in Huntsville, Ala., in a point-to-point mode rather than in a comprehensive network mode, using a pair of Dante MY16-AUD cards to connect 32 channels of the church's Yamaha M7CL 48 FOH console to a digital recording system running on an Apple MacBook Pro laptop. The two cards, three Ethernet cables, and an eight-port network switch cost under $1,500, but economics wasn't the only reason the company chose Dante.
"We've been bench-testing Dante for a while and we've found it to be more flexible than CobraNet or EtherSound," says Brian Pearce, CTS Audio project manager, who also cited its "ridiculously low" latency, making it a good choice for music-intensive applications. But he also cautioned that integrators used to the more ubiquitous CobraNet will have to build their infrastructure slightly differently to take advantage of Dante's redundancy features. "Unlike CobraNet, Dante does not hook both the primary and secondary cables to the same network switch," he explains. Instead, Dante's primary and secondary cables go to separate network switches.