Dear Friends,
Fireworks, political conventions and AudioLink Specials - what more can you ask from July?
This issue includes articles, information and links concerning:
- Wireless Microphone Systems: How They Work and How to Choose One
- Specials on Wireless Microphone Systems
- Responses to Customer Questions
- 45% Off List on DJ Beginner and Intermediate Equipment Packages
- Handheld PA and Megaphone end of the Summer clearance
Wireless Microphone Systems: How They Work and How to Choose One
As an audio technician, I have witnessed a revolution in the conference industry.
Just about everybody wants a wireless microphone -- “like the ones they use on TV”.
As sound quality and reliability have increased and cost has decreased, wireless microphone systems have become very popular. They have thrived for one important reason: eliminating the microphone cable connection frees you to walk across the stage, among the audience, (and, sometimes, out the door). This gives the presenter greater mobility, flexibility, and, if you're like me, and prefer the wireless, hands-free models -- the ability to talk with your hands!
So what is a Wireless Microphone System?
A wireless microphone system is usually made up of three components:
- the microphone (either handheld or hands-free),
- a transmitter, and
- a wireless receiver.
In the case of a handheld microphone, the transmitter is built into the microphone itself.
For the hands-free microphone, a short cable connects it to a body pack transmitter. This unit usually looks like a transistor radio and has a clip for attaching to a pocket or belt. This configuration is used for a number of “hands-free” microphones, lapel (or lavaliere) mics, collar mics and headband mics
How does a wireless microphone system work?
First the microphone provides the audio signal.
A conventional wired microphone converts sound waves into an electrical audio signal that travels to the PA system through a cable. A wireless microphone system goes one step further, and converts the audio signal created by the microphone to a radio signal (UHF/VHF) or an Infrared signal.
Then the transmitter broadcasts that signal through an antenna.
Transmitters are available in two basic types. One type, called a "body-pack" or "belt-pack" transmitter, is a small box about the same size as a TV remote control. The transmitter clips to the user's belt or may be worn on the body.
In the case of a handheld wireless microphone, the transmitter is built into the handle of the microphone, resulting in a wireless mic that is only slightly larger than a standard wired microphone. All wireless transmitters require a battery (usually a 9-volt alkaline type) to operate.
The job of the receiver is to pick up the signal broadcast by the transmitter and change it back into an audio signal.
The output of the receiver is electrically identical to a standard microphone signal, and can be connected to a typical microphone input in a PA system or a closed system headset.
Wireless receivers are available in two different configurations: Single Antenna or Diversity.
Single antenna receivers utilize one receiving antenna and one tuner, similar to an FM radio. Single antenna receivers work well in many applications, but are sometimes subject to momentary interruptions or "dropouts" in the signal as the person holding or wearing the transmitter moves through "dead spots" in a room.
Diversity receivers provide better wireless microphone performance. A diversity receiver utilizes two separate antennas spaced a short distance apart and (usually) two separate tuners. An "intelligent" circuit in the receiver automatically selects the better of the two signals, or in some cases a blend of both. Since one of the antennas will almost certainly be receiving a clean signal at any given moment, the chances of a dropout occurring are greatly reduced.
NOTE: Each performer or presenter using a wireless system at a particular location (a theater, church, or school, for example) must use a system operating on a different frequency. Wireless systems at one location cannot "share" frequencies because they would interfere with each other, just as if two radio stations in one city tried to broadcast on the same channel. If two performers at one location try to use the same frequency at the same time, neither one will be picked up clearly. This potential for interference limits the number of wireless systems that can be used simultaneously at one venue. The technicians at AudioLink can assist with selecting the appropriate frequencies for your needs.
Choosing the wireless system which is right for you!
Choosing a wireless microphone system is really a series of choices relating to the individual components (input device, transmitter, and receiver) that make up the system, and their suitability for your specific application.
The input device and transmitter are chosen based on the source to be miked. For example, some typical input device/transmitter combinations and their applications are:
- a handheld microphone with built-in transmitter (for vocalists)
- a lavaliere or lapel /tie-clip microphone and body-pack transmitter (for lecturers or stage actors)
- a headband microphone and body-pack transmitter (for singers/dancers or aerobics instructors)
For example, UHF is more expensive but has a wider range of operating frequencies. Then too, there is a school of thought that infrared systems are more secure than FM systems. This may have been true in the past, but with more modern technology both are subject to interception and the real decision comes down to personal preferences and the operating environment. (e.g. infrared is limited to line of sight broadcast, while FM systems may be subject to frequency interference).
Transmitter choices often revolve around the difference between UHF, VHF and infrared.
Choosing the type of receiver - single antenna vs. diversity - is more a function of where the wireless system will be used, rather than what it will be used for.
Single antenna receivers perform well when operating distances from transmitter to receiver are short, or in environments where the likelihood of signal dropouts is low. Diversity receivers should be chosen whenever operating distances may be longer, when the transmitter user may walk behind walls or through doorways, or in environments where the potential for dropouts is greater due to the presence of metal structure or external sources of radio frequency interference.
How a Wireless System Connects to your PA System
A wireless system connects to the rest of your PA system in the same way that a standard wired microphone connects.
Almost all wireless receivers put out a signal that is electrically identical to that of a wired microphone. The output jack of the receiver simply connects to the same input on the audio mixing console, mixer/amplifier or PA system. Because each user may be talking or singing at a different volume, each wireless system must be connected to a separate input on the PA system so that the level of each wireless microphone can be adjusted individually. Depending on the type of input connections that your PA system has (XLR or 1/4 inch), you may need an adapter cable to properly interface the output of the wireless receiver to the input of the PA system.
Ask us at AudioLink about what type of connectors, if any, you'll need.
Next month I'll be focusing on a particular type of transmitter/receiver system that incorporates both digital and analog features.
In the meantime Click Here for the latest Specials on wireless microphone packages at AudioLinks.com
Responses to Customer Questions
Here are some more of the questions asked by our readers and customers.
Karleen R. writes "I was looking at the Anchor MiniVox and was quite impressed. I would like to know what you have that is PORTABLE but will be loud enough for a whole school (600 kids) to hear. I also would like a cordless headphone mike. Thanks so much for your help!"
We replied:
Dear Karleen,
I recommend the Anchor Audio MegaVox Pro Basic Package with built-in wireless receiver.
I talked with Anchor Audio and they assured me that this system will easily cover an audience of 600 kids and you have the option of choosing either a handheld, headband, collar or lapel microphone. By purchasing a package you also get the advantage of discount pricing on cables, stands and microphones - which works out to be lower than buying the system piecemeal.
Hope this helps!
NOTE: This brings up the whole issue of coverage with PA systems. Our suggested rule of thumb is one watt per person. That said some manufacturers (like Anchor Audio) prefer to use an RMS (Root Mean Square) calculation which suggests much greater capacity for a given wattage. In general, we stand by our rule of thumb approach as the safe way to go, but so far -- in the field -- the Anchor ratings have held up pretty well. So if you have non critical or audio friendly environments the RMS calculations may be more than adequate for your use (and you can also save some money)!
Here's another inquiry, this time from Karen M.
"I am looking for a wireless system capable of broadcasting at least 3 channels of audio simultaneously with at least 8 receivers which can be switched to the channel the user wants to listen to. We would like to rent the system initially for a 3 day project then possibly purchase the system after we see how well it works. Thank you."
And here's our response:
Dear Karen,
I recommend you take a look at the multi channel tour guide system which is available for sale OR rental.
The system gives you the ability to transmit simultaneously on up to four different factory tuned FM frequencies. The basic 2 channel system comes with eight 4-channel FM receivers, but you can order as many more as you need.
Rent the system for a tryout if you like, but I gotta say - you're gonna end up buying it anyway because of the superior quality and excellent price! It even comes with a heavy duty suitcase that adds a professional look as well as offering sturdy protection and custom made storage.
Hope this helps!
Feel free to get involved with your own questions or comments. We address them individually, and in each issue I highlight some of the more useful examples.
Introductory Offer on DJ Beginner & Intermediate Equipment Packages
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Up to 45% Off List Prices on these high quality packages!
Learn More
Handheld PA and Megaphone Back-to-School Special!
Is it that time of year already?
Well -- yes!
And here at AudioLink, it's time for falling prices (just in time for the change in seasons)! l
Megaphones and Handheld PA systems -- perfect for steelyards, assemblies and small auditoriums -- just choose the model that fits your need and your budget!
Learn More
Meanwhile, here's a sampling of our Current Specials if you're in the market for a solution to your presentation requirements:
Fender Deluxe Passport PA Systems, and compatible Fender speaker stands or wireless microphones at great discounts!
AudioLink is now featuring Fender portable PA systems including the Fender Passport Deluxe 150 and Fender Passport Deluxe 250 as well as compatible wireless microphones: Fender wireless hand-held microphone, Fender wireless hands-free microphone, Nady VHF wireless two channel microphone system, Nady VHF wireless lavaliere microphones, and the fully compatible Anchor Audio UHF wireless microphone system.
Learn More
Guitar Gear and Music Collectibles - extraordinary discounts plus a FREE GIFT!
Begin your collection of Fender media products and collectibles and get a free gift to start up your collection. For a limited time only, with every $50.00 purchase of Fender Books, CD's, Videos, DVD's and Collectibles, receive a Fender Collectible coffee mug.
Learn more
AudioLink Services
You already know that AudioLinks.com is the premiere source for audio equipment discounts, but are you aware of the other services we provide?
Conference & Meeting Planning, Equipment Rental, Interpreting, Recording & Transcription as well as Voice Over Production are just some of the other areas of the industry we can help you with.
Let us give you a Free Consultation and you'll find out just how versatile we really are!
Well, that's about it for this edition. In future issues we plan to offer reports and updates on different types of audio equipment, links to useful sites and to answer questions posed by you and other readers. We hope you will find this newsletter useful and we welcome your feedback.
Looking for something that's not on our web site? Contact Us and we'll respond as quickly as possible, or, visit AudioLink's product pages and see for yourself why we are known as: "The Home of Sound Solutions"
Until then,
That's sound advice...
Regards,
Audio Man
SiteManager@audiolinks.com
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