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Straight Talk with team el-j: the use of public airwaves

This Straight Talk displays some of the ins and outs of the importance of audio during an event. el-j’s partner, Kelly Epperson, gave us the inside scoop of the importance of the choosing the right wireless microphone systems for a meeting or event and provided information about public airwaves the changes that are occurring in the United States. Kelly has worked in audio system design, mixing and RF coordination for over 25 years.

What are some considerations when our clients are choosing microphone systems and using wireless microphones?

There are a number of things to consider when choosing the right system. Some considerations are the type of meeting that is being conducted, confidential information being shared, wireless systems being used around the area and mitigating interference, the country the event is being held, equipment availability, and of course cost.

What are some questions you address frequently when preparing a client for an event?

1- How can I ensure that other parties aren’t eavesdropping?

With a product like Shure Axient Digital, encryption is easily enabled to prevent unapproved receivers from intercepting the microphone signal.

2 - Can anyone unauthorized listen when I am presenting confidential material or speaking in off-mic conversations?

If the wireless microphone signal is not encrypted, then it is technically possible for unauthorized parties to listen in.

As we have seen in the past couple years, individuals who are being interviewed or participating in a television show, for example, might be having their conversations recorded between takes since many times the recording devices are not necessarily stopped each time.

3 - What happens if a member of the press or another wireless device interferes with my microphones and how do mitigate those risks?

One of our standard practices is to inquire if there will be any press invited or even the corporate communications department for the company we are work with on a project. If so, I will ask to be connected with those individuals in order to pre-assign frequencies, so they can use their wireless systems during the event without interference to either party.

For events open to the press, it is a similar procedure but typically more detailed and begins prior to the press’ arrival if the event is expected to have a large press contingency.

4 - What procedures should be put in place from the beginning of the project?

Always communicate to the production company if any outside crews will be allowed into rehearsals, the meeting or event and if they will be requiring the use of wireless microphones or a connection from the audio mixer.  It’s always important to know who is being given a direct audio feed or even can pick up sound within the room.  (Press, corporate communications, webcasts, etc.)

5 - Can I remotely change the frequency of the transmitter when a presenter is on stage?

It is possible to change the frequency of a presenter’s microphone remotely if interference is detected.  My system of choice is the Shure Axient products.  This offers the greatest insurance against wireless microphone interference.

6 - Is a wired mic ‘more secure’ than a wireless microphone?

Yes and No. Yes- technically you cannot wirelessly eavesdrop on a wired microphone.  However, if you are offering direct feeds from the audio mixer for the press, corporate communications, simultaneous translation or even webcasts, it is imperative that there is a clear understanding of when content should never be sent during a rehearsal for instance.

Why does this matter for our clients?

Like other wireless technology in use today (Wi-Fi and cellular), convenience brings with it additional challenges.   When a client works with a trusted production company like el-j, they can rest assured that our team is taking all these into consideration.  For instance, as new technology like Shure Axient Digital has become readily available throughout the world, we have begun using it on as many events as it’s available.  Also, with the ever-changing RF landscape, we provide an RF coordinator.  This allows us to mitigate risks as much as possible. Not technology is perfect, but we work hard to ensure the best possible outcome.

What is the incentive auction from the FCC and how does it affect future events that el-j will be producing?

In 2016, the FCC began the process of auctioning off RF spectrum in the television broadcast band. In the past, these frequency blocks were utilized by TV broadcasters to transmit television signals and we were allowed to operate our microphones and intercom in unused spectrum depending on the city we were working. With predicted wireless data device usage set to grow exponentially, more frequencies were needed by the telecom companies such as AT&T, Verizon, T-Mobile, Sprint, etc.

This was called an incentive auction because both the broadcasters and the U.S. Government received the payments from the winning telecom operators.  Besides the short-term gain of revenue came directly from the auction, telecom taxes over the lifetime of the companies would be considerable.

The frequency ranges auctioned were desirable for the telecoms for two reasons.  First, the lower frequencies allowed the wireless telecom devices to work more effectively in urban areas with large buildings and other structures. Secondly, the ability to purchase operating frequency ranges that were contiguous across the entire United States made it very appealing to the telecom.

So, what does this mean for el-j and their customers?

This has resulted in myself and my RF coordinators doing more prep before arriving on site for load in to ensure we have systems that legally can operate in the spectrum available as well as planning for other users in the area.  Many times, we will work in the same city multiple times in just a month or two’s time and notice an increase in cellular traffic in just a week’s time.  That means we have to ensure our mics don’t operate in that area both from a legality perspective and equally important that the mic will work interference free.

el-j is hired to make sure our clients don’t have to worry about all of this, but what should our clients know about these new regulations?

Any microphone and intercom systems built after a certain date are no longer allowed to be manufactured in the frequency ranges that were auctioned off.  After 2020, it will be illegal to operate in the same frequency range as the cell phone or wireless data devices. In fact, if the broadcaster has released their channel assignment and the winning telecom has activated their systems in those markets, it is illegal to operate devices in that range.

Legality aside, the end user wouldn’t want to risk using devices in those frequency ranges simply because you couldn’t be guaranteed that your presenter’s mic wouldn’t be interfered with during the presentation.

If you have any questions about production or AV technology, please call team el-j!  We're here to help.  Ed Baldi: and  John Bettini:

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