Finding Interoperability in Unlikely Places
     

interoperability routing consoles X192 wheatstone standardsThe author is vice president, engineering at Wheatstone Corp.

How many times have you lost your car keys or wallet, only to find it was in your pocket all along? It seems our search for studio interoperability is no different.

As engineers, we’re always looking for new standards that can solve problems and make life easier. That’s why I am a member of the Audio Engineering Society Standards Committee X192 task group. I have no doubt that the work we are doing there will result in interoperability standards for audio, some of which are already tried and tested in our WheatNet-IP AoIP system.

For example, a lot of our automatic discovery technology for polling the AoIP network and adding new devices as they come up is also being pursued by the X192 task force.

But what is missing in the open standards discussion is the fact that for us broadcasters, studio interoperability already exists. In terms of being able to pot up a fader from two rooms away or turn mics on and off, raise or lower levels on processing, and select mixers or codec gear from anywhere in the AoIP network, we’re already there. And have been for quite some time.

An infrastructure already exists whereby broadcasters can control the entire studio, from the automation on down to the microphone level. And in case you’re wondering, we can do all this and control levels, set gain and do so much more without having to run a slew of individual apps from different vendors.

I know of a thousand or more stations that are doing exactly that, all day, every day.

Ironically, the reason why we are so far ahead in this regard is because of open standards. IEEE standards like TCP/IP, RTP, IGMP, and so many others are what make interconnectivity feasible and interoperability between sources, devices, consoles and studios possible. Without these, we wouldn’t have been able to design an AoIP system with true IP and Ethernet connectivity, which in turn makes it possible to control consoles, devices and studios through a common interface: the intelligent network.

Every single device in our WheatNet -IP system, from the largest console to the smallest button panel, connects over IP and communicates using these standard protocols, giving every device visibility and control of every other device on the network. This is the ultimate goal of the standards groups and Wheatstone and its partners are already there.

Even those earlier methods that are used in lieu of true IP, such as the CAN bus, RS232, RS485, etc. serial bus protocols used in other AoIP systems to connect consoles and IP engines, are standards-based. As limited as these are in their ability to pass on the full control and logic necessary for true interoperability due to their point-to-point connectivity, they are stepping stones along the way.

The same goes for early audio standards like MADI, which is still going strong, as evidenced by the racks full of MADI I/O boxes and intercoms out there. It’s the reason we added a MADI port to our Blade IP access unit; we wanted studios to interconnect to all that gear that existed throughout the facility, and we recognized that a MADI interface could create that bridge for broadcasters.

In truth, interoperability exists on so many levels already. All the metering packets, command controls — starts, stops, audio processing — all the intelligence that needs to exist to oversee a large networked audio system, all that is taking place in studios today.

So what new open standards are we really talking about here? Specifically, we’re all examining the protocols and standards needed to solve latency and clocking issues when dealing with multiple streams of audio in the context of the economic advantages of Cat-5 cables, issues that are of critical importance to pro audio more so than the everyday radio operator.

After all, it’s the pro audio guys who have to deal with OoS, or lack thereof, inherent in IP when covering live, staged events that require sending multiple audio streams to large speaker clusters in a stadium, for example. And the pro audio market, being many times larger than the broadcast market, has many more device types and manufacturers to deal with. That’s why the AES is trying to develop these standards.

We’re interested in these standards as an industry because AoIP manufacturers also deal with clocking and latency issues to varying degrees, and Wheatstone is no different. Lacking a sufficient standard for this, we all have developed our own clocking schemes for striking that balance between the amount of buffering needed to align audio packets in time and the very time it takes to buffer the audio samples, hence latency.

Wheatstone’s approach is somewhat different than other manufacturers because our system happens to run on a later, and therefore much faster, generation of IP connectivity protocols. One gigabit/second transference, compared to others’ 100 mbp’s network speed, gives us a more acceptable latency versus buffering tradeoff. You don’t have to specifically choose to make a stream low-latency; they all are.

It’s understandable, then, that AoIP manufacturers lacking the network speed, especially those focused on the pro audio market, would look to new standards to help solve some of those problems and give them the ability to connect their devices together and pass audio between them.

One of our goals for the AES-X192 task group is to create this standard so that one day you’ll be able to stream your console monitor output directly to your X192-enabled power amplifier or speakers. Protocols like Ravenna are a good first step.

In the grand scheme of things, we all benefit from open standards. But while we’re searching for the next open standard to solve these and other issues for the entire audio industry, it helps to remember that the Holy Grail of true interoperability can be found in a good many broadcast studios today. All we have to do is look.

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