Some background for those who have not been following this closely. The "airwaves" are a public resource, and use of that resource is governed by the Federal Communications Commission. The FCC issues licenses for individuals and companies seeking to broadcast – everything from TV and radio stations to cell phone companies.
Wireless mics first appeared in the 1970s and they eventually moved into the UHF TV part of the total spectrum. These are the TV stations above channel 13. Even though TV stations were already there, we found space between the TV stations in which to operate our mics and, later, wireless monitors. But it is important to note – even though officially a license was required, the audio biz (except for some very big operations) did not get licenses. We operated under what is called Part 15 of the FCC code, which basically allowed us to operate under a specified power level as long as we did not interfere with a licensed user (referred to as a Part 74 user).
That worked pretty well until the wireless explosion we have been seeing for about a decade, in which every church and school and bar has at least on wireless mic, and the rapid adoption of in-ear personal monitors made the available space even more crowded. And as society in general has become more "wireless," with cell phones and Wi- Fi everywhere and new consumer devices planned, the war for UHF began. First, the spectrum above 800 MHz was auctioned off, and then, as of June 21, 2010, using wireless mics in the 700 MHz range became illegal. The remaining war was over the use of the UHF space in the 500 and 600 MHz ranges. On one side, audio providers. On the other, Google, Microsoft, Yahoo… Get the picture? So that brings us to Thursday, Sept 23, when the FCC handed down its final decision on what devices will be allowed in that spectrum and what kind of protection they will get from other devices.
New Boundaries
Okay, just a forewarning. There will be a significant amount of conjecture and opinion from here out.
First, the actual decision. Wireless mics, instrument packs and IEMs are covered under Section 15. OK, not all systems are. All systems under 50 milliwatts are covered under Part 15. There are commercial systems capable of much higher power, and those still require a license.
Back to what the Part 15 thing means in a moment.
Pro audio did not walk away with a total loss. The FCC agreed to put aside two UHF TV channels of bandwidth in every city specifically for wireless mics. It appears that these spaces may change slightly from city to city based on what spectrum is currently being used there. The FCC order says these channels must be the closest available to channel 37, which is reserved for radio telescopes.
So let's bottom-line this. A UHF TV "channel" consists of about 6 MHz of bandwidth. And two of those are reserved in each city. Using current analog technology, we can squeeze 12-16 channels of wireless into that space. That's for the total space provided by both channels. Remember, stereo IEMs take about 40 percent more bandwidth, so probably 10 IEMs max.
That number might work fine in BF, Egypt but, to use an example that I have worked and know pretty well – in, say, downtown Las Vegas where there may be four to six bands playing on the same block and sometimes in the same building, this can get tricky.
New devices operating in the UHF will periodically have to query a geo-location database that lists pre-existing spectrum users, but the average wireless mic user (read ANY audio rental or touring company) will not be included in the database.
"I Was Here First."
This is where we get back to the guts of the Part 15 thing again. Just by virtue of being bound by the rules of Part 15, we give tacit agreement to accept interference from other Part 15 devices. Actually, as wireless guru Henry Cohen pointed out in the Wireless World group on ProAudioSpace, it is not tacit approval, it is a regulatory condition of operating these devices. Yes, that means what you think it does. If your show and the one next door are stepping one each other's wireless, there is no one for you to go to and get them to intervene on your behalf. It also means that, outside of the bands reserved for wireless mics, we also have to accept interference from any other device approved to operate here under part 15 rules. And it is not just us. ANY wireless user licensed or not, can operate in that spectrum – churches, news crews, hotels, schools – oh, and your shows.
Next issue. While most pro wireless units give you 100 or more frequencies from which to choose, they are between a set pair of upper and lower frequencies. For example: I am looking at a stereo IEM transmitter that is on my desk right now. It offers 100 frequency choices. But all of those choices lie between 614 and 647 MHz. If, as expected, the protected channels are 36 and 38, then I'm safeish between 600 and 607 MHz and between 615 and 621 MHz. So the unit I am looking at can use the upper part of the protected spectrum. But more than four-fifths of the frequencies this unit can use lie outside that protected spectrum. I can use it, but above 621 MHz it is an "at my own risk" thing.
"A Key Win"
Lest we forget that pro audio is not really a part of the greater consumer electronics industry, note that EVERYWHERE outside of the industry this is seen as a major win for commerce and consumers. This from CNET on the day the ruling was announced:
"As part of the new rules adopted today, the FCC agreed to set aside two channels for wireless microphone use to mitigate potential interference issues. But the commission said it would not require device makers to include geolocation spectrum sensing technology in new devices to ensure that these products don't interfere with existing services already using the spectrum. This is a key win for device makers, because it means that they do not have to include the potentially expensive technology in their products.
"Instead, devices will query a special geolocation database that makes sure no one is using that spectrum before it transmits. This database check is largely to prevent white space services from interfering with broadcast TV signals."
Audio folks involved in this issue for a long time are looking at the decision as a win, and several of the companies that plan to make and market the new consumer devices are pissed that the FCC "overprotected" wireless mic users.
For those of you who have not followed this, or need a refresher, consumer electronics and Internet service providers have been trying to get this spectrum for a new generation of handheld wireless devices like, say, the iPad, but without the 3G cellular connection. You know how there are Internet "hot spots" in lots of businesses? Those currently use the 2.4 GHz band, which is controlled by international agreements and is non-licensed. But as you know, if you have a wireless router in your home or office, the range is limited and coverage can be spotty.
But when it comes to wireless, smaller numbers are better. A signal in the 500-700 MHz range has a much longer waveform than one in the 2.4 GHz range, and longer waves travel farther and go through obstacles like walls much better. So, getting all of those hot spots to move to 500 MHz routers could potentially create a citywide hotspot that anyone could access. It can also be used to provide wireless access to remote and rural areas where running a cable is not practical. So there are a lot of good things that will come out of this. Just not good for those of us in pro audio.
"Relative Chaos"
To quote Don Boomer, who heads up the digital wireless effort for Line 6, "The FCC sees that another batch of unlicensed frequencies will offer economic development and provide the country with a new super Wi-Fi. Ever since the Balanced Budget Amendment of 1997 and, more recently, the proposed National Broadband Plan, it is apparent that the core TV band will be in relative chaos for near future."
For the official word from a number of manufacturers, please see the sidebar to this story.
But, Boomer has it right. This spectrum is going to be fought over for the foreseeable future, and when the pro audio biz goes up against the Microsoft/Google/HPs of the world, we are going to come up short every time. As is usually the case, the solution will be technological, and like so much in our live audio world, the future is probably digital.
Steve LaCerra has a rundown of the available digital stuff right now in this issue on page 38, and there is a review of the latest Line 6 digital wireless mic on page 29. But the short version is that AKG, Lectrosonics and Line 6 all offer digital wireless for live performance right now. Neutrik is slated to ship a system in the next moth or so. The advantage of digital is that because the A-to-D conversion happens in the mic or beltpack, you are no longer transmitting audio. You are transmitting data. And when it comes to data, it can be error corrected.
As others have pointed out to me, digital does not solve the basic problems inherent in any RF system, nor is it immune to interference, and error correction means processing time, and that means latency – the constant thorn in the side in digital audio.
In a performance situation, digital wireless audio can work kind of like the Internet itself does on a much smaller scale. Because the transmission is data, multiple versions of it can be sent over different frequencies and put back together at the receiver before the D-to-A conversion. So if your data takes a hit on one frequency, the processor in the receiver says, "Oops, there's a glitch. I'm gonna grab that data from this stream over here where it is undamaged." And what comes out sounds like a continuous audio signal. But again, what level of latency is okay for your gig?
Bottom Line… For Now
So where do we end up for now? The devices that will eventually cause us problems are not even on the market yet. But I fully expect to see first-generation versions at the Consumer Electronics Show in January and to see them in use by, probably, April of 2011. The folks who make them are telling the FCC 2012 and anything they come up with will have to go through a pretty rigorous FCC approval process so that later estimate might be right. But I, for one, am not waiting around to find out. We have the two channels that have been set aside, and the spectrum between channels 14 and 21 will remain off-limits to these devices as well, although we will still have to wedge our way into the holes in that space. So the sky is not falling today. There are a lot of smart people developing products in this industry, and ways will be found around this. But for now? Hang on, it's gonna be a rough ride.
From the Manufacturers' Perspective
FOH asked all of the major wireless makers for comment – not spin – following the latest FCC ruling. Here are a few of their answers. Of course, all of them are going to talk about why their stuff is great. But there are at least hints here about future direction. Read between the lines…
Jackie Green
VP, R&D and Engineering
Audio Technica
We are pleased that the FCC recognized the importance of wireless microphones to the many users who have come to rely on them, and happy that unlicensed use is now accepted across the entire TV spectrum. This FCC Report and Order (R&O) defines an environment that has opportunity for many types of wireless devices, and reminds us that wireless microphones must use the entire TV band spectrum (channels 7-51) and use it efficiently in order to share this space with the many devices that will emerge. Audio-Technica products are technically well-positioned to operate in the environment defined September 23 by the FCC's R&O. We have products that operate in the VHF range, we have products that operate below Channel 21, and we have products that operate in the two reserved band ranges. We have products that work well when many simultaneous channels are needed, and we have products that operate well even when used in channels adjacent to TV.
Audio-Technica has always maintained a commitment to continuous improvement and reliability of wireless microphones in the increasingly crowded RF environment, and the FCC R&O has opened the door to our future investment in technical development by making it clear that wireless microphones are here to stay.
Audio-Technica is uniquely positioned as a wireless company going into this new spectrum era. We vacated the 700MHz band more than eight years ago, we have products that work in the lower bands, and we have exciting new SpectraPulse UWB digital technology that operates entirely outside the broadband and TV Band Devices (TVBD)-white space area. We have proven our ability to look ahead to give our customers reliable products, and we look forward to increasing these efforts now that the FCC has recognized wireless microphones and opened the door to opportunity.
Karl Winkler
Director of Business Development
Lectrosonics, Inc.
Lectrosonics wireless equipment has always been well-regarded by working professionals who have to "make it work" in very tough RF environments, even when high channel counts of 60+ channels are required. A combination of high-power transmitters (50 to 250 mW), transmitter filtering, receivers with robust front-ends and Digital Hybrid Wireless® technology gives these products an edge for such challenging applications. As the RF noise floor continues to rise, these same technical factors will prove even more valuable to users in the future. Lectrosonics was one of the first manufacturers with a pure digital system for professionals (the data-encrypted 700 Series) and continues to invest heavily in R&D for future digital transmission platforms for the standard UHF band and also in other parts of the RF spectrum. Products like the D4 multi-channel digital wireless system in the 902-928 MHz ISM band have already been successfully adopted for TV and film production and for live sound applications.
Don Boomer
Microphone Product Line Manager
Line 6
Ever since the Balanced Budget Amendment of 1997 and, more recently, the proposed National Broadband Plan, it is apparent that the core TV band will be in relative chaos for the near future. The FCC believes that another batch of unlicensed frequencies will offer economic development and provide the country with a new Super Wi-Fi. So to be able to dodge the oncoming freight train, we developed a digital wireless system that can operate in the 2.4G ISM band even though there is a lot of RF competition present. It is unlikely that there will be any changes to this band in the near future as it is overseen by an international agency and agreed to by a treaty of 191 nations.
FCC Commissioner Michael J. Copps' statement on Sept. 23's second MO&O called for "wireless microphone manufacturers to make much-needed improvements to equipment efficiency and interference resistance." Our Line 6 XD-V digital wireless systems were designed to operate in crowded RF environments from their conception. Our system basically sends small packets of coded digital data over multiple frequencies (frequency diversion) so that the impact from other RF signals is significantly reduced as interference is not likely present on all of the channel's frequencies. Error concealment ensures no interruption of audio if all the data does not arrive intact, much in the same way a scratched CD is still playable without errors. Our data coding, combined with error detection and frequency diversity, allow XD-V systems to operate without the necessity of a clear channel and ensure that the only audio that ever passes through the receiver is the intended audio from the transmitter. The XD-V digital systems are simple to operate, require no scanning for channels and have no gains, squelches or pads to set. They also enjoy superior sonic quality as the system is free of companders.
Joe Ciaudelli
Director of Market Development & Education
Sennheiser
On September 23, 2010, the FCC released a ruling on Television Band Devices (TVBD). This ruling updates the guidelines the FCC previously released on November 4, 2008. TVBD are a new class of unlicensed consumer device that will primarily be used for broadband access. Like wireless microphones, they will operate on locally unused TV channels. Sennheiser customers have been concerned about this issue because more devices using the same frequency ranges increases the potential for interference
In their ruling, the FCC reiterated their recognition of widespread use of wireless mics throughout our society and the need to protect them from interference. They are demonstrating this by reserving two TV channels for wireless mic operation in every city. This will allow operation of at least 16 mics for all users; some cities will have additional channels closed to TVBDs and available for mics.
Licensed users, such as broadcasters and their content providers, will be able to reserve still more channels through direct registration in the forthcoming spectrum database.
Unlicensed users operating in professional performance venues can also apply to protect additional channels during performance times by electronically filing a request with the FCC at least 30 days in advance. Sennheiser hopes the FCC builds a system that will be easy to operate and highly responsive to legitimate requests.
In their commentary, the FCC stated that wireless mic technology is spectrally inefficient. However, Sennheiser has made significant progress in this area with the recent introduction of its new SK5200 II and SK5212 II transmitters. These devices are able to operate in a low intermodulation mode, allowing more mics to be packed in a smaller range.
Sennheiser will continue to innovate; nevertheless, we believe the FCC may not yet fully appreciate the technical hurdles required to increase efficiency without sacrificing performance. Wireless mics must be compact, operate without drop outs, exhibit negligible latency, and have full audio frequency response. No other technology comes close to meeting these performance requirements, and we will continue to communicate these points with the FCC.
The bottom line is that wireless microphones will remain as vital tools in audio systems. Sennheiser will continue to manufacture reliable equipment as well as provide top-level support. This includes its on-line tools (frequency finder and quick reference TV channel charts), its Sound Academy educational seminars, and its expanded menu of RF services.
Chris Lyons
Manager, Technical & Educational Communications
Shure Inc.
The UHF TV band is gradually becoming more crowded, and many VHF DTV stations are migrating to the UHF band to improve signal coverage. In any given city, the open TV channels are now typically scattered throughout the band rather than clustered together. At events where large numbers of wireless systems are deployed, sound engineers need to be able to take advantage of available spectrum throughout the entire UHF band.
In Shure's popular UHF-R, ULX, and SLX wireless systems, we increased the number of available frequency ranges, in some cases covering the entire U.S. UHF TV band. In addition, Shure designed the UHF-R wireless system with a wide 60 MHz tuning bandwidth so that the system can roam wide in search of clear frequencies. And Wireless Workbench 5 software makes coordinating and deploying frequencies across multiple bands easier than ever. Together these give sound engineers maximum flexibility to utilize clear spectrum wherever it may be.
Doran Oster
President & CEO
Sabine, Inc.
The FCC proposed the current changes in the white-space allocations (450MHz – 800MHz) almost 10 years ago. That is why all of Sabine's wireless microphones have been designed to operate outside of the white-spaces since we first started production about seven years ago. Sabine's SWM4000 and SWM6000 series operate in the 915MHz band and the SWM7000 operates in the 2.4GHz band. We are very happy to announce our SWM6000 series was recently nominated for this year's TEC – Technical Excellence & Creativity Award.
Sabine wireless systems are not affected by the recent rulings and they are shipping now.
