By Llanor Alleyne

With the advent of wireless microphones and conference systems, the most obvious advantage has been freedom from cable runs, which can cost both time and money. The ensuing design flexibility can be a godsend to consultants, integrators, and clients.

“There are instances where table-installed microphones are just not possible,” said Alicyn Frenchman, sales engineer for West Chester, PA-based integration firm, Advanced AV. “Additionally, ceiling microphones are not ideal due to ambient noise created by HVAC systems. There are times where running cables are not possible or add too much cost to the project. Wireless microphones provide the flexibility for motion without the interference of cables. When designing for audio conferencing, wireless microphones that have been properly set up work wonderfully.”

The embracing of wireless mics and conference systems does come with caveats, however. Due to transmission issues (interference, white noise, etc.) these systems can be lacking in the performance department.“

That wireless microphones have improved in sound quality and reliability is certainly true, but they still can’t match the performance and reliability of a $30 mic cable,” said Ray A. Rayburn, principal consultant for K2 Audio in Boulder, CO. “We use wireless where appropriate to the needed functionality of the system, but don’t view this as simplifying the system design and implementation. Simplicity at the expense of lower reliability and higher cost (both initial and running costs) is usually not a trade-off that is an advantage for our clients.”

Practical Considerations

The bane of wireless technology is interference. Wireless microphones and conference systems are no different. Signal degradation can make a perfectly working system conk out at the most inconvenient time—a consequence the client will not be interested in understanding when they are in the middle of a performance, presentation, or meeting.

Harry Allison, director of audio visual design at Waveguide Consulting in Decatur, GA, recommends site surveys as a preliminary measure before over promising systems to clients.

“Wireless technologies have susceptibility to interference from a wide range of common sources,” Allison said. “Care should be taken by performing site surveys whenever possible, but this can be tricky. For example, in a corporate situation, site surveys can be performed before the building is complete, however many of the sources and behaviors that could interfere with the wireless system performance are not in place until after the client has moved into the space and begins to use it. One may never know for sure that there could be a problem until after the client moves in and begins to microwave their burritos and use their hands-free phone sets.”

Another precautionary measure is to ensure that the recommended system is up to the task it is meant to perform as Rayburn pointed out. “The more channels in use in a single system, or in a small area, the better quality the wireless systems must be to ensure trouble-free operation,” he said. “Inexpensive wireless can be fine for one to four channels, but as the channel count increases so does the radio frequency performance needed and therefore the cost per channel. With the best gear today it is possible to use as many as 80 to 100 channels in a single system.”

Perhaps the simplest consideration of all, however, is the battery life of the installed wireless system. Like interference,a dead battery and the subsequent lost of power can raise the hackles of the end-user.

“Battery life or charging time can be critical particularly in heavily used spaces,” said Chris Bell of consulting firm, AVAYE. “Ensuring that spare batteries are available or microphones are charged properly is critical to a working system.”

Human Error

Most clients don’t have the luxury of an in-house technical team to blame for an embarrassing incident where human error is squarely to blame. What this comes down to, and is a manifesto for any product worth its salt, is ease of use.

Making end users aware of live active microphones is one primary issue,” Frenchman noted. “If you are wearing a wireless lavaliere microphone, you need to know where the mute button is so as to not be broadcast inadvertently. Conference system manufacturers have gotten a much better at providing visual cues with the use of LED lights to show when a microphone is on and off or an alarm sounding if you are to leave a conference room. That certainly helps in preventing human error.”

Both Rayburn and Bell emphasized battery monitoring as well, with the former calling for usage timers on rechargeable batteries and the latter suggesting that spare batteries be always at hand along with the proper labeling of microphones to make the systems operator’s job a bit easier.

Ultimately, taking wireless mic and conference systems control out of the hands of the client seems to be the only surefire way to avoid uncomfortable broadcast incidents, with many integrators agreeing that a client lockout is in the best interest of all involved.

“As an integrator we are big believers in locking the client out of the myriad of options (especially frequency selection) available on modern wireless systems,” said Per Forsberg of Audio Architects in Chippewa Falls, WI. “Also, because such a large portion of our business is house of worship, we like top-mounted toggle switches to mute audio or turn a transmitter on and off. Clergy need a tactile switch that they don’t need to look at to know if they are on or off.”

FCC Regulation

Earlier this year, in measures to complete the large-scale digital television transition, the Federal Communications Commission ordered all wireless microphones users to vacate the 700 MHz band by June 12, 2010 to make way for public safety agencies and licensed wireless services providers. Manufacturers have already begun to offer rebate packages for wireless microphones and conference systems that rely on this band for operation, but the ruling also offers integrators unique business opportunities.

“The change allows for a conversation to occur and a reevaluation of technology and applications,” said Advanced AV’s Frenchman. “It benefits integrators to initiate the exchange of wireless microphones in frequency ranges that have been banned by the FCC . There will be a cut-off, but if you get caught ‘stepping’ on an emergency frequency, you will be fined severely.”

Forsberg has also used the ruling to get reacquainted with his entire customer base to help them make the transition if necessary. “Often they don’t have an issue, but they know we care and we refresh our relationship,” he said.“Other times we can help them tune away from the 700MHz band and sometimes we generate new business with replacement wireless systems. All of these scenarios are positive experiences.”