For the past nine years, I’ve had the privilege of working the floor at NAB Show in Las Vegas for Radio magazine. The primary focus is to represent the magazine on the exhibition floor, make contact with vendors and see what products we engineers would find interesting over the upcoming year. A common “vibe” or element generally manifests itself halfway through the first day of exhibition floor investigation.
For example, just a few years ago, flat-panel LED lighting was all the rage, and it was of great interest to the radio folks who wanted to delve into video. Prior to that, HD Radio widely dominated the conversation, of course.
|The exhibit floor drew a large and curious crowd, as usual.
Some NAB Show trends are easy to spot, and others require a little more digging.
This past April, by the end of day one, the term “AES67” buzzed about consistently. After the third booth visit, when “AES67-compliant” rolled off the tongue of the exhibitor, I finally said, “OK, let’s back up. Give me some details.”
After a crash course and some subsequent research, I’ve come up with a quick history and simple description with the hope that it sheds some light on AES67 and why radio broadcasters should pay attention.
A QUICK HISTORY
Most audio and radio techs are familiar with AES3. It’s a digital audio standard that was put forth by the Audio Engineering Society and European Broadcasting Union in 1985.
AES3 spelled out a groundbreaking digital format that eventually made digital audio products talk nicely with one another. The AES remains a household name (although there are others) in developing interoperability standards for the audio industry.
The AES continued its work in providing cross-platform continuity when it unveiled AES67 in September 2013. It’s a product of the AES-X192 project, headed by AES Fellow Kevin Gross that addresses standards for networkable AoIP (audio-over-Internet Protocol) gear.
Gross and his team came together with the understanding that the current protocols used by different broadcast audio manufacturers are actually very similar, but the dissimilarities create a brick wall when it comes to interoperability. Deploying a standard to make everyone compliant with one another was a reasonable undertaking.
Nearly three years after its conception, AES67’s debut was a big deal in Las Vegas.
A SIMPLE DESCRIPTION
Prior to the implementation of AES-EBU in the mid-1980s, the interconnection of equipment that supported stereo PCM formats was — for lack of a better term — a crapshoot. The AES-EBU standard allowed PCM or DAT formats to work interchangeably at different clock rates.
AES67 accomplishes the same objective, but it is set in place for audio systems that exist together on IP networks. It calls for agnostic data protocols to be used in the Ethernet Layer–3 world. The Ethernet layers are spelled out by the Open Systems Interconnection Model, on which the Ethernet standard was built. The OSI Layer–3 is the “network” layer and it determines many of the critical factors that affect audio transport like quality of service and host naming, for example.
Since I am far from a networking expert, it will be sufficient to say that the AES67 framework of rules allows differing IP audio products to see and recognize each other.
Let’s make an analogy with speech: You speak English and a colleague 3,000 miles away speaks German. However, you both speak French, so you use French to communicate.
Another analogy that I heard on the exhibition floor: You speak English into a telephone, but your French-speaking colleague understands it as French. Conversely, he speaks back to you in French and you understand it as English. The two of you are able to conduct regular business as usual because the language differences are no longer a hindrance.
Here’s a real world example: A station using Wheatsone- or WheatNet- or Axia Livewire-compatible consoles could transport its program via audio over IP to an Orban 8700 at the transmitter site. We can even consider Tieline’s Genie and Merlin products; both are AES67-compliant and will interface with WheatNet in such a way that the Genie and Merlin appear as sources or destinations in WheatNet’s Navigator software.
I have personally experienced situations where other radio networks aren’t able to connect to my facility (and the other way around) because we both have different IP codec products. If all stations were AES67 compliant, the world would be a much simpler place!
AES67 is not an effort by the AES-X192 team to replace anything — it simply offers an interoperability standard. It works alone, but can be used in concert with popular transport protocols such as Dante and Ravenna.
One good example of this integration is the Simple-IP-8 from Arrakis Systems. The 1RU device is powered by Dante and is AES67-compliant. From a form-factor perspective, the Simple-IP-8 is loaded with 8-mono or 4 stereo inputs and outputs connected through RJ-45 jacks. This allows a studio to launch itself into the AoIP world with an IP-based transport management system that is compliant with AES67 gear anywhere on earth.
AES67 is heralded as well in live sound and music and post-production circles. Imagine a scenario where a fixed or touring live sound system is in place, a broadcast truck rolls in and a recording rig shows up. If all three entities have AES67-compliant AoIP gear, the setup time is greatly reduced and the show goes on with less routing headaches. Each system plugs into a central IP switch and instant magic happens.
Another standard you may hear more about in the near future is AES70, a scalable, control protocol for professional media networks. AES70 addresses device control and monitoring only; it does not define standards for streaming media transport (that’s AES67’s role). It will work in conjunction with AES67 as well as Ravenna and Dante.
AES67 is a groundbreaking advancement. It frees up purchasing and installation restraints. If an installer wants to use WheatNet-compatible consoles, Telos Hx6 talk show systems, Orban processors and Comrex codecs, he can, and they all operate together with newfound interoperability via AES67.
This was a dominant theme at NAB Show in Las Vegas, and AES67 certainly won’t be confined there.