Steve Harvey /
01.17.2012 12:42 PM
The Changing Face of Audio Routing

LOS ANGELES: A presentation at the DTV Audio Group meeting during the recent New York AES Convention highlighted an operational difference between many European and U.S. broadcast audio infrastructures, particularly in remote trucks: the use of the console router instead of a patchbay. Although large-scale analog audio patchbays would seem to be redundant in today's increasingly all-digital static and mobile plants, there appear to be various barriers to a more widespread adoption of the onboard software router available in digital broadcast consoles.


In many European OB vehicles, console software routers are used instead of the large hardware patchbays more common in the U.S., such as this example in NE P's Denali Summit truck, with audio engineer Hugh Healy. Photo by The Recording Academy/ ©2011. Photograph by John Shearer
Switching from racks of metal patchbays and associated copper wiring in a truck to a GUI-driven in-console router would offer major weight and cost savings, of course. But in the opinion of Steve Zaretsky, vice president, broadcast sales, Solid State Logic, a patchbay allows easy reconfiguration in situations where there are multiple users or applications. Plus, in emergencies, "If you have to get around an issue, if you don't have a patchbay, you're a lot more limited in what your emergency plans can be."

That said, there has certainly been a move by broadcasters toward the use of MADI—an AES standard—as a distribution method, reducing the use of copper significantly. "Even if you're doing a lot of patching, the interconnectivity has been really cut down by implementing MADI," Zaretsky said.

Zaretsky further noted, "In the studio environment we've seen more of our customers starting to utilize the console's audio routing facilities for communications, de-embedded audio and control signals, all within the MADI architecture. As one of the founders of the MADI spec we're very happy to see broadcasters recognize that the low latency point-to-point routing offered by MADI is still an advantage over newer network based protocols."

Although MADI, a 25-year-old format that carries up to 64 channels, initially disappeared from recording studios along with Sony DASH machines, the broadcast industry has embraced it over the last five or more years. According to Dave Letson, regional director of sales at U.K.-based Calrec, "Pretty much every truck that we're involved with now has several MADI boxes, and each of our boxes has at least two connections." Some consoles use multiple MADI connectors to interface with the router, comms, recorders, and other trucks, he added.

But Mike Franklin, senior sales manager for Studer, noted that there are stumbling blocks to the adoption of a console's onboard routing facilities, including the implementation of the GUI and the protocol for patching a source through a DSP channel to an output. "Ten console manufacturers have 10 ways of doing it," he said, noting that Studer's multi-touch screen offers a streamlined solution. "How well it gets managed on that patch screen is the difference in ease of use between consoles."


Letson additionally noted a move toward SDI. "You put an SDI input on a console and you feed that with the SDI stream and pull off the channels that you want. That can be done via the router—and it's still the video router; you do not have to have a separate audio layer." At the same time, said Letson, Calrec is receiving more requests for the console to be controlled by the router with a third party control system.

This was echoed by Zaretsky who also noted the increased demand for more studio-integrated solutions on both sides of the Atlantic.

There's a challenge there, too, according to Franklin: "The protocol that's used for switching within routers is old." That protocol, Pro-Bel's SW-P-02 and SW-P-08, doesn't allow for certain switching within combined streams, he said. "You can use translators but there are issues with how things work." The industry can expect protocol updates over the next year or so, he believes.

Many console manufacturers' distribution and routing systems are essentially I/O systems, according to Rusty Waite, president, Stagetec USA in Atlanta. In contrast, Stagetec—as well as fellow German manufacturer Lawo—takes a different approach. "We're a router company that has built consoles onto a router rather than a console company that's trying to build a router," he noted. That experience has allowed the company to overcome challenges such as timing, clocking, sync, stability, and implementing different flavors of I/O cards, he said.

Most importantly, stressed Waite, Stagetec's Nexus router, which can break out to numerous protocols and connectors, offers decentralized control, unlike a console's router. Depending upon the permissions set for the system, anyone can have access from any point on the network to route any signal anywhere without having to bother the A1. For example, Waite said, a single network-connected Nexus base device can access ESPN's entire 20,000 x 20,000-point router setups in Bristol or L.A.

On a smaller scale, Logitek, to take one example, manufactures TV broadcast consoles following a similar paradigm to Stagetec, where the console is simply an operating surface on a router system. The core Audio Engine can replace part or all—as many as 32 engines may be combined—of the house router, as a result. Engines may be physically separated according to fiber specifications: up to 600 feet apart using multimode, 10 km with single mode.

But while there's no reason for U.S. broadcasters to not already be using MADI, Waite continued, "MADI is not the future; the real future is AVB [Audio-Video Bridging]." The IEEE-developed future A/V transport standard is backed by major corporations such as Cisco and Broadcom: "They're going to push it forward and we're going to be able to piggyback on there."

One significant advantage is that AVB utilizes Cat 5 cable, noted Waite. "You could clip a Cat 5 and leave it behind. Try telling that to someone who's laid a DT12 cable!"

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Posted by: Anonymous
Sat, 12-22-2012 06:10 PM Report Comment
Customer review from the Amazon Vine™ Program (What's this?)As a dbaatase administrator and programmer, I tend to enjoy tech toys. I have a D-Link DIR-825 Xtreme N Dual Band Gigabit Router sitting on my desk, and was excited to be offered the D-Link DIR-685 Xtreme N Storage Router as a more visually appealing and versatile router. The D-Link DIR-685 Xtreme N Storage Router offers high speed wired and wireless n connections. Wireless connections can be managed by zones including guest connections. Unlike most routers, the DIR-685 includes network-attached storage (NAS) capabilities and a digital picture frame. The initial set-up was simple to complete, however testing revealed the network didn't set up correctly. My PC can connect directly to the network, but cannot access any wireless networked devices even though I can ping them. I called customer support, only to be given the run around by people who didn't understand my problem. I asked my other half who is more familiar with networking to speak with customer service. This is when they admitted they didn't understand the problem and escalated to a specialist who would call back later. When the specialist called, the result was basically since I can ping the devices it's not a router problem. So I'm stuck with a network which doesn't work properly and have no clue how to fix. The router frequently freezes up and drops connections. Freezing is obvious thanks to the digital picture frame as the images just stop rotating. It is not uncommon for me to unplug the router three times a week or more to unfreeze. Meanwhile there is no telling when this unstable router will drop a connection. Since the router sits on my desk, it's easy enough to disconnect and reconnect the network cable, but I'm tired of listening to my other half's constant valid complaints. The digital frame is a nice touch; however it is way too small. For proper viewing the router would need to be pretty close to the viewer. This may cause a conflict between viewing and placing the router in an appropriate spot for wireless connectivity. Anyplace with too much distance makes the photos too small to distinguish. I really enjoy using the frame channel with the digital photo frame. Setting up an account at the frame channel website was simple. I was able to sign up for news, weather, sports, stocks, and magazine sites as well as images from my facebook friends. With the digital picture frame, the router includes an intuitive menu selection for showing stats and settings. The NAS drive (hard drive not included) was also simple to install and put to use. As a techno-geek I was excited to try out this router. However my network isn't working properly, while D-Link customer service was unwilling to help resolve the problem. The router freezes and drops connections regularly. If I weren't having connectivity and freezing issues, I'd be willing to invest more time determining the networking issue. This problem is huge for a router and overshadows the digital picture frame and NAS system. This router has potential to be a fun versatile device, but I cannot recommend purchasing an expensive product which fails at its primary purpose. PROS: Frame channel Intuitive on-board menu display NAS (network-attached storage) system CONS: Never got it to work properly Customer service not helpful Digital frame too small Regularly freezes and drops connections

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