glenn Posted October 3, 2010 Report Share Posted October 3, 2010 A Discussion on the Future of Wireless Microphone Use It's recently been announced that wireless broadcast frequencies will soon be open to white space devices, this makes the future of wireless microphone use nothing like what has come before. Interference from computer-based devices utilizing white space spectra will greatly diminish the range and reliability of today’s analog FM wireless microphones. These new users will be broadcasting wide band digital data that will appear to analog FM wireless as an increased noise floor. While it will not decode into audio, it will limit the usable range of wireless microphones. The problem is that the number of new users is unlimited and will most likely be many times the current wireless user base. At any given time white space devices could outnumber wireless users 1000 to 1 since these new users will be on a computer or even gamers using some sort of new Nintendo type product to play wireless against friends during school lunch. There is no other frequency spectra we can use that will provide the same reliability our current UHF allocation does. Frequencies above about 900MHz do not easily go through walls or bodies and are subject to dropouts. Lower VHF frequencies require large antennas making them unpractical. In the announcement it was guaranteed there will be two clear TV channels per location, but there's no way this will support the needs of our industry moving forward with traditional analog FM wireless. In order to use a large number of wireless channels simultaneously in the future the microphones we use on a daily basis must change. The following is what Zaxcom is doing to actively combat these future changes so our industry can handle this new reality. Since only 12 MHz is currently slated to be interference-free you'll have to fit as many channels of wireless into that area as possible. To do so, microphones must be free of the intermodulation artifacts that limit the usable amount of channels. Without intermodulation, RF channels can be evenly spaced allowing the available spectra to be used in the most efficient way. Wireless microphones will need to be flexible software definable radio systems, the type of system that can change its occupied bandwidth and modulation type at will to suit specific needs. For example, when 20 microphones are needed on a reality show they'll need to be set to the most narrow bandwidth, say 50 to 100 kHz per channel. This way two to four times the number of channels can be used together. If a few milliseconds audio delay isn't an issue, audio compression can be utilized to get the bandwidth down even farther, to allow even more channels per MHz. Conversely, if only a few microphones are needed, a standard 200 kHz channel can be utilized to obtain the best audio quality and lowest delay. Another key element is the ability to remotely control wireless over RF, not only for convenience purposes but out of necessity. For instance, during a football game there's a need to use large numbers of wireless both on the field and during the half time show. Remote controllable wireless gives you the ability to shut down the game mics while the halftime mics are enabled, allowing shared use of frequencies by multiple sets of transmitters. Internal backup recording will become a necessary safety net. When all else goes wrong, the production sound mixer will need to rely on the single thing that is guaranteed to deliver pristine audio every time since the reliability of audio transmitted wirelessly will almost always be subject to interference. Transmitting two channels over a single RF carrier. Where possible as with 2 channel camera links transmitting 2 channels per RF carrier cuts the number of required frequencies in half. Because of what the future holds, we feel analog wireless won't hold up in a digital world. Digital wireless has so much more to offer, just a few examples are digital dropout protection, minimization of occupied bandwidth, and transmission of two channel on a single RF carrier. Digital also offers the benefit of encryption, protecting the audio content from unintended listeners. Audio that sounds just like a hard wire is only a bonus! On October 30th Zaxcom is holding a seminar at Coffey Sound demonstrating how the Zaxcom Digital Wireless series is in tune with the future and available today. We hope you can attend. Glenn Sanders President Zaxcom, Inc. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 3, 2010 Report Share Posted October 3, 2010 Thanks, Glenn, a nice summary. " Internal backup recording will become a necessary safety net. " This excellent capability will not be useful in live situations, of course... " Transmitting two channels over a single RF carrier. " Transmitting two or more channels over a single RF carrier. change gonna' come!! Quote Link to comment Share on other sites More sharing options...
Izen Ears Posted October 3, 2010 Report Share Posted October 3, 2010 This is slightly terrifying. It's very heartening for Glenn to post here, it shows a clear concern and proactive approach to this potential company-destroying white space thing. I wonder what the wireless manufacturers' plans are? I guess they'll all have to go invent the on-board recorder on all their transmitters, and we will all have to go buy new systems unless we were smart enough to go Zax... Dan Izen Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted October 3, 2010 Report Share Posted October 3, 2010 I'm sure all of the manufacturers are working very hard to produce wireless for our use that will deal with these challenges. Of course, Zaxcom has had a significant headstart with the introduction of their game changing all digital wireless microphone systems and the Zaxcom line of wireless that are available today. I used the Zaxcom wireless I think back in 2001 but had not even thought about the implications for the future of all wireless mics. I was fortunate that when I finally had to make some new purchases when my old Audio, Ltds became unusable, I got into the Zaxcom Digital wireless. The Zaxcoms have already saved me in several difficult situations, with features and functions that just are not available anywhere else. The remote control feature, even before Zaxnet, has been terrific, and the facility to scan and find clear airspace has worked flawlessly. It will be interesting to see what everyone else comes up with. I am sure the other companies will come up with something in the future; I am just thankful for Zaxcom producing what I believe is a fairly future proof wireless today. Regards, Jeff Wexler Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 3, 2010 Report Share Posted October 3, 2010 None of this is new, we have all known about this and been discussing it, for years! " they'll all have to go invent the on-board recorder on all their transmitters, " the huge majority of wireless microphone systems are used live " what the wireless manufacturers' plans are? " all of them are actively working on this; the hugest majority of wireless microphones are used by other than Production Sound Mixers. " we will all have to go buy new systems unless... " no "unless" about it, just as NAGRA's and DAT's had to be upgraded, even Zaxcom's systems will continue to advance; their current units are not yet capable of all the tricks that Glenn mentioned needing for the future... change is certain! and... change gonna' come! Quote Link to comment Share on other sites More sharing options...
glenn Posted October 3, 2010 Author Report Share Posted October 3, 2010 ; their current units are not yet capable of all the tricks that Glenn mentioned needing for the future... Zaxcoms current product line is fully capable of all of the features that were talked about in the initial post. Glenn Sanders President Zaxcom Inc. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 3, 2010 Report Share Posted October 3, 2010 wow, I stand corrected... owners and users of today's Zaxcom products will have no need to replace them to enjoy all the additional features and capabilities of future models or to comply with future regulations... In our world of "planned obsolescence", a promise of no obsolescence is a very persuasive selling point Quote Link to comment Share on other sites More sharing options...
glenn Posted October 3, 2010 Author Report Share Posted October 3, 2010 While we can not be 100% certain what might be neccessary in the future we have tried to make a product that can adapt. Zaxcom Wireless is currently programmed for 3 modulation types. US mono, US Stereo and EU mono. Nothing stops us from developing new modulations and updating the software to impliment them. Of course recording, remote control and no intermodulation are also current features. Glenn Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 3, 2010 Report Share Posted October 3, 2010 " very persuasive selling points " Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 3, 2010 Report Share Posted October 3, 2010 moving this topic forward: one advancement path that the manufacturers have been taking is development pf wireless microphone systems that have capabilities to cover wider swaths of spectrum; this proves to be valuable in finding clear spectrum spaces more readily, although with issues of performance of lower Q (selectivity) RF systems, and technological techniques to deal with those issues. I'm still getting excellent results with fixed frequency VHF units! another thing to keep in mind is that not only do "they" interfere with "us", but "we" interfere with "them", and as the data devices will probably be frequency hopping, "we" will drive "them" to hop away! change gonna' come! Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 4, 2010 Report Share Posted October 4, 2010 " The FCC’s recent TV Band Device ruling has garnered support across the wireless microphone industry, most recently from Audio-Technica. " "the original rules issued two years ago, which included the spectrum-sensing requirement... The elimination of the sensing requirement is a defeat for broadcast lobbyists, who fought tooth and nail to retain it,.. “It’s clear that the FCC carefully considered the needs of wireless microphone users while crafting this order,†said Sandy LaMantia, president and CEO of wireless mic maker Shure. “The reserved channels will provide a safe harbor in which musicians, small theaters, houses of worship, and businesses can operate their wireless microphone systems without interference from new TV band devices.†" http://www.televisionbroadcast.com/article/106892 http://urgentcomm.com/policy_and_law/news/fcc-grants-white-space-20100929/ the devil is in the details: http://arstechnica.com/tech-policy/news/2010/09/fcc-white-space-rules-inside-the-satanic-details.ars and here is the bad news that brought this topic back to active and heated discussions: http://www.fcc.gov/Daily_Releases/Daily_Business/2010/db0923/FCC-10-174A1.pdf Quote Link to comment Share on other sites More sharing options...
tlarvenz Posted October 20, 2010 Report Share Posted October 20, 2010 Thanks very much for the post Glenn! I've been saved several times from drop outs by the on-transmitter card recording. It's a safety net that was the main incentive for my purchase and I'll be adding several more to my kit. When are we going to see quantum entangled devices? ;-) Thanks again. T Quote Link to comment Share on other sites More sharing options...
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