A New Direction for AVB: Time Sensitive Networking (TSN) for Industrial Control

For many years, I've been following and have written a lot about IEEE Audio Video Bridging (AVB), an open standard way of transmitting audio and video over Ethernet using special network switches. It's a fascinating standard, but in the live show audio market, it seems to me that AVB has been eclipsed by Audinate's proprietary Dante technology, which has been meeting our needs for some time (at CityTech, for example, we've been distributing audio for our Gravesend Inn haunted attraction using Dante since 2011.)  More on that subject in my post-Infocomm writeup here.

As a result of writing these pieces, last Fall I met Greg Schlecter, Technology Marketing Strategist of Intel, who told me about new developments in a fascinating new direction for AVB, for another industry that needs precise, timely delivery of data: industrial control. This work has been under way for some time; as part of the effort, in 2012, the IEEE Audio Video Bridging standards task group was renamed to the "Time Sensitive Networking" (TSN) task group to reflect the new, larger focus of the group. And late last year, the AVB trade association AVnu Allance released more information; you can read more here on their site, in their press release here, and in a 30 minute Youtube video here.

This effort is fascinating to me since in addition to being a live sound guy, it just so happens that I wrote a book about live show applications of industrial control technologies. But what does audio have to do with industrial control, which is used in factory automation, medical devices, elevators, oil refineries and to control all kinds of machinery? AVB was originally designed to transport audio over standard Ethernet networks; to do so, it has to be able to work to a very high degree of time precision. Pro audio, for example, often uses a sample rate of 48,000 samples per second, and the precise synchronization of those samples for playback is critical for digital audio to work properly. In addition, on live shows we often have to send signals far and wide around a facility, but typically not over the internet (unless it's streamed, which is typically a different specialty). Modern Ethernet is well suited for both of those needs.

Industrial control has similar needs. For example, a factory may have large machines spread out over a facility, which also need tight synchronization. For example, if the parts of a Twinkie manufacturing facility aren't precisely synchronized, there could be a gooey mess on the floor:

Note: That footage has no audio; if you want to see a peculiar mash up of Twinkie manufacturing footage with Van Halen music, click here.

I wrote in my book about the limitations of standards, the process of standards development and adoption (excerpt here); one fascinating thing that we often see is the unintended directions standards can take after they are released into the wild. MIDI Show Control, for example, was developed to control all kinds of things on a show, but these days mostly is found connecting lighting desks.  DMX was designed for dimmers, but now controls things like video servers. And while the live show industry share of the industrial control market is tiny, sophisticated stage machinery is finding an ever-larger home in live shows, and we often use controls equipment from large industrial controls manufacturers. Big companies like Intel and GE are involved in the TSN effort, so it's possible that this will gain traction in the controls market soon, and it's possible that AVB will still end up backstage as a backbone for scenic automation systems.  Let me know if you see TSN showing up on your stage.

Spooky Sound Story: Simon Kearns' Dark Waves

Back in 2010, I did some research on sub-audible sound called infrasound, and how those low sound waves might be responsible for supposedly "supernatural" experiences. In 2011, I got an email from Simon Kearns in Europe, who was writing a "rationalist" ghost story, and was incorporating infrasound into his story. 

I read a draft of Mr. Kearn's Dark Waves in 2013 and enjoyed it, and the book is finally now available!  

The Illusionists on Broadway

The first magic show I remember seeing as a kid in the 1970's was also the last magic show I saw on Broadway: Doug Henning's The Magic Show. Today, I saw The Illusionists on Broadway with my friend Bonnie A, and I really enjoyed it. The show features seven magicians, each with a different specialty. And in this version of the show (they seem to change the acts around depending on where the show is produced), there happily wasn't one "watch while my assistant crawls around inside this box" illusion, which I always find cheesy.  Here instead, each of the performers demonstrated quite a bit of skill in their respective disciplines, the acts were well ordered and the show was paced well.  I love figuring out magic tricks, and I figured out all of them except for one by Kevin James--a beautiful number performed in the audience for a little girl.  But it's really fun to be fooled.

They made good use of video for the close up acts, and I liked the lighting. The sound mix seemed fine, but unfortunately, in the top of the mezzanine where I was sitting, the sound coverage was inadequate and there was very little high frequency coverage, so everything was too quiet and muffled, in the notoriously dry and acoustically dead Marriot Marquis theatre. They had a standard touring line array setup so in the orchestra it probably sounded fine, but for the very high price of tickets even in the mezzanine, the sound should have been better. I think the sound problems led to a feeling of disengagement for those up in the seats near me--you could hear the applause much more strongly from below than from those up top. No sound designer was credited, so I'm not sure what happened.  And apparently the fill speaker you can see in my crappy Instagram photo was not working today:

In any case, the show tours through June, go see it!