AVnu Alliance Audio Wireless

Started by concordal, January 15, 2014, 09:38:53 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

concordal

Special Report: The State Of Production Audio Wireless


http://www.prosoundweb.com/article/special_report_the_state_of_production_audio_wireless/live


An interesting read.  One implication: Used wireless (e.g. IEM) could be prone to interference because of radio spectrum reassignment.  Despite its title, article lacks meaningful detail about present-day spectrum and potential interference. 

====
Special Report: The State Of Production Audio Wireless
Top RF consultant James Stoffo discusses the picture for wireless system use...
Jan. 07, 2014,

By now, we should all be well aware of the fact that our production audio "RFscape" is changing dramatically due to the introduction of digital consumer devices within the wireless microphone spectrum. The next two years will separate the women from the girls and the men from the boys when it comes to wireless audio operation in the United States.

It's becoming more and more difficult to operate multiple wireless systems, including microphones, in-ear monitors, IFB, and intercoms, on events and installations. We have overcome the energizing of digital television (DTV), the "700 MHz" auction, and are preparing for the mass introduction of white space devices in the U.S. and around the globe. And the FCC is already speaking of further auctions within what is left of the production audio wireless spectrum.

Though these additional auctions are scheduled for next year, it may be years before they actually take effect. I heard the first mention of digital television in 1991 but it was not fully adopted until 2009. This means that we likely have time to prepare and properly plan. As long as we know what to plan for, I believe that we'll get through the next wave of electromagnetic assault on our wireless systems relatively unscathed.

Making It Work
Let's start with what we do know as fact. We've been forced to operate all of our wireless audio in about half of the spectrum that we've had since 1962. Next year, with the introduction of white space devices en mass, we'll need to work with less than 10 percent of the UHF spectrum that we've always had. The Fixed and Portable digital consumer devices that we'll be sharing radio spectrum with must follow very strict guidelines.

The two types of white space devices have two distinct sets of rules, so it's a good idea to understand the differences between them. Fixed devices may operate anywhere in both the VHF and UHF radio spectra; however, they cannot operate adjacent to any local TV station. This means that you may operate wireless microphone and intercom systems adjacent to TV stations when planning for Fixed White Space Devices. 

Portable White Space Devices may only operate above 512 MHz (or TV channel 21) and do not have to obey the adjacent TV channel rule. These will be the "smartphones" in your audience that may really create havoc within wireless systems. The FCC has left the pro audio community with a total of 12 MHz of radio spectrum to operate within, including mics, IEMs, IFBs and intercoms.

The only way to make that work will be to properly band plan. It's always a good idea to separate base transmitters, such as IEM and intercom transmitters, as far away as possible in terms of frequency from base station receivers, such as wireless mics and intercom receivers. This keeps the overall RF noise floor low and guarantees the best range and audio quality from wireless audio systems.

In addition, find out which specific two 6 MHz slices of spectrum are reserved for wireless systems in the city in which you're operating. These two TV channels will change from city to city and the information is available to anyone in advance. They will always be the two closest open TV channels above and below TV channel 37. TV channel 37 goes from 608-614 MHz, so this rule will change after the next auction—but will certainly be in effect for the next few years.
Knowing The Rules
As wireless operators, we're at a point in time where the only way to achieve success will be to continually know what the rules are. And yes, they are changing.

For example, the next auction will place everything above 600 MHz on the chopping block. This means that we'll lose another 100 MHz of UHF spectrum. At that point, wireless will literally need to be "reinvented" from a manufacturing standpoint to survive.

Wireless system makers are well aware of this fact. Between the introduction of digital wireless mics from AKG, Shure, Sennheiser, and Line 6, and the return to the VHF band for wireless intercoms from Radio Active Designs (a company I'm involved with), we're seeing a rebirth of technologies in the audio community. This new approach represents a necessary evolution in our industry and has been brought on by the catalyst of FCC spectral changes and digital consumer technology.

As the majority of consumer digital technology will be in the UHF band, it's a good idea to seek safe harbor in the VHF band wherever possible. This may include placing IFB systems in the 76-88 MHz band and intercom systems in the 174-216 MHz band. Between these two, you can buy yourself an additional 100 frequencies and get some "wiggle room" up in the UHF band for your wireless mic systems.

I've worked with the new digital wireless microphone systems from all of the professional manufacturers and can make a usable observation. A digital wireless system will always be more tolerant to interference than an analog wireless system. All analog wireless systems in the U.S. use Frequency Modulation (FM) technology.

Though FM sounds great and has no latency, it is not very forgiving when it comes to interference rejection. In fact, the slightest interference may cause an FM system to become unusable. The digital wireless systems on the market today are extremely tolerant to interference and can operate with a very high general noise floor inside of their radio band.

Since the portable white space devices will be everywhere in your audiences, my feeling is that they will consistently create intermodulation distortion products that may cause interference that's harmful to wireless systems. Remember, these smartphones will be in the same radio spectrum as your wireless mics. It really seems to make sense then that any equipment placed in this band should be as tolerant to interference as possible. (Hello digital wireless mic systems!)

Planning For Success
Let's bring things all together. Wireless audio system operation has gotten more and more difficult over the last few years. It will be even more difficult in the coming years.

Know where to operate for your best chance for success. Spread out wireless systems in frequency with proper radio band planning. Use VHF wherever possible for wireless IFB and intercom systems. Budget for digital wireless mics over the next few years. 

Review the latest rules regarding where wireless audio devices and white space devices may operate. Know the two 6 MHz channels that are reserved for wireless audio in your city or cities of operation. Keep IEM transmitters in one of those 6 MHz chunks and wireless mics in the other to maximize signal-to-noise ratio, distortion, and audio quality.

And finally, stay informed about possible upcoming changes and new technologies. Stay tuned!

James Stoffo is the founder of Professional Wireless Systems and a founding member of Radio Active Designs. He continues to work as the RF technician and frequency coordinator on large-scale special events and installations.

Elantric

The Wireless Audio landscape is changing rapidly -

other sites to be aware of
AVnu Alliance tests and certifies devices for interoperability, providing a simple and reliable networking solution for AV network implementation based on the Audio Video Bridging (AVB) standards.
http://www.avnu.org/

http://www.avnu.org/news_and_events/cedia_roundtable
AVnu Alliance Holds First CEDIA Installer Roundtable for AVB

Integrators and IT Specialists Share Industry Knowledge to Help Shape AVB for Residential Applications.

Beaverton, Ore., October 4, 2013 – AVnu Alliance, the industry forum that certifies Audio Video Bridging (AVB) products for interoperability, held the first AVnu Alliance Installer Roundtable Breakfast during CEDIA Expo 2013 with the goal of understanding the unique challenges and demands of custom installers that could be solved with AVB.

The Alliance has recently completed research and market requirement for wireless audio distribution and chose to initiate a roundtable discussion at CEDIA Expo 2013 to discuss use case, best practices and field-related information regarding residential installation among a small group of like-minded integrators. The roundtable served as the next step in the development of the Alliance's market and the technical certification documents for consumer and residential audio and video products.

Serving as a forum to gather information about today's installation challenges in the residential space, the Installer Roundtable brought together influential and knowledgeable industry integrators who could share experiences and talk through use cases for AVB. The attendees included: Shawn Lemay, founder and owner of Sound & Theater; Jesse Miller, integrator with Myriad Home Entertainment; Jeff Mitchell, director of projects and systems for Robert Saglio Audio Video; and Jeff Terzo regional sales manager for RS Pro Sales.

Alliance members Greg Schlechter from Intel, and Denis Labrecque from Analog Devices moderated the roundtable, initiating conversation with general background on AVB and AVnu Alliance and encouraging questions and suggestions from the other participants.

"Wireless bridging solutions would be helpful in the multiple dwelling unit market and right now those solutions use a lot of bandwidth," said Jeff Mitchell, CEDIA certified installer and CEA TechHome member about wireless audio via AVB. Other installers in the roundtable mentioned the need for wireless when retrofitting a location, wiring between buildings and as a must have for control systems.

Mitchell also mentioned: "Our industry is going more end-to-end but what we still really need are less expensive and more reliable diagnostic tools to accurately identify problems within the installation. Currently there is no easy way for us to know what is working incorrectly."

Having technology that is certified to work on the IEEE standard network could give installers an industry standard tool to solve that problem. "The Alliance has set up a certification program to ensure that products will work in harmony. That's going to be a promise of AVB Certification from AVnu Alliance. We guarantee that the device conforms to the specification," said Alliance member, Denis Labrecque, ProAudio Business Development manager, Analog Devices. "I am an audio guy, and for me AVB is a whole new world. We need to hear from installers working in this industry to help us share and shape the future of residential audio and video installations."

"AVB is better plumbing." Greg Schlechter of Intel and AVnu Alliance Board of Directors member touched upon the benefits of AVB, "One of the key capabilities required for network AV distribution is time synchronization. AVB makes this a fundamental capability of the network."

"CEDIA's purpose is to actively educate the installer and bridge that gap with the installer and IT," said Shawn Lemay of Sound & Theater, who has been involved in commercial and residential electronics integration for 25 years. AVnu Alliance believes that AVB is the foundational solution to bridge the IT and AV gap, and thus CEDIA Expo was the perfect timing to bring together experts in the field to explore the adoption of AVB standards for reliable, time-synchronized streaming of audio and video media.

Designed to meet the demanding needs of high-quality, real-time synchronized audio and video through guaranteed bandwidth networks infrastructure, the open IEEE AVB standards make a compelling solution for residential applications. AVB has already been adopted in many demanding markets including automotive and professional audio.

Manufacturers interested in joining or learning more about the AVnu Alliance may contact adminstration@avnu.org.

About AVnu Alliance
The AVnu Alliance is dedicated to the advancement of streaming audio video by promoting the adoption of IEEE 802.1 Audio Video Bridging (AVB) standards over the network infrastructure. The organization strives to create an open path to AVB standards, define AVB compliance test procedures, and an AVnu certification program that ensures AVB interoperability of networked A/V devices to provide the highest quality streaming experience in professional A/V, automotive, and consumer applications to deliver a compelling end user experience. .

Press Contact
Caster Communications, Inc. 401-792-7080
Kimberly Lancaster klancaster@castercomm.com cell: 401-829-0111
Kelly Ahern kahern@castercomm.com


admin