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For obvious reasons, most instructors choose to use wireless headset mics.  Don’t be put off by these systems; if you can operate your television or radio, you can operate a wireless system just fine – it’s really the same thing.  Let’s look.

 Modern systems are designed to be simple to use and understand.  Each system includes a transmitter and a receiver – simple.  These operate on a specified frequency so that one receiver looks for signals from one transmitter – simple. The receiver connects to a line input on your mixer and is treated just like any other source.  Just remember that if you intend to have multiple instructors working wirelessly at the same time, even if in another room, each system must operate on a different frequency.  To help sort this out, manufacturers provide multiple pre-programmed frequencies designed to work with each other. Different systems have varying sets of frequencies available.  The ability to utilize more and more frequencies – and more systems -- is one of the primary factors in varying levels of pricing.  Multi-frequency or “frequency agile” systems are more costly than fixed frequency, or “non-agile” systems. That said, just about any model system will allow for 2 to 5 similar systems at a time. 

 You will see the term “diversity” used a lot in wireless system literature.  This simply describes how the receiver looks for signals from the transmitter.  In a diversity system, 2 antennas are looking for the same signal; the one that finds the strongest signal is used, helping to ensure a consistent reception with fewer drop-outs (receiver’s loss of signal).  Unless your receiver is right beside you with no obstacles or people in between, look for a diversity reception system.  Diversity systems are by far the most widely used because of their added reliability.

 Wireless systems are also described as either VHF or UHF.  This is just like the channels on your pre-cable television.  The VHF range (channels 2 through 13) got pretty crowded, so manufacturers moved to UHF, looking for more available frequencies.  You are much less likely to encounter interference with a UHF system.  What kind of interference?  This is the range where TV stations broadcast.  If your area has a channel 45 broadcast over the air, for example, you will need to avoid that frequency. Frequencies in wireless systems can be expressed as the actual frequency (656.012 MHz, for example), the corresponding TV channel (45, in this case), or any other manufacturer designation (AA, BB, 7 or anything else).Your wireless systems sales representative will help select a set of frequencies for use in your area.

 In fitness applications, look for a water-resistant, stable and comfortable headset – avoid the super-small earpiece style mics that you may see presenters wearing.  They will move around too much.  You know, right tool for the right job and all that.  Almost all headset systems use a bodypack transmitter; a wire on the back of the headset connects to the battery–powered transmitter.  Samson, however, makes a headset with a small, lightweight transmitter built-in, eliminating the need for a bodypack.  Both systems work very well, so the choice is yours. While several manufacturers make water-resistant or even water-proof headsets, there are also water-proof transmitters available.  Remember the trainer riding Shamu at SeaWorld? All wireless - a great voice-saving alternative for water aerobics classes.

So, now that you are the resident expert on wireless systems, let’s look at what you can do to make your system last longer.  These things take a lot of abuse in a pretty tough environment, so proper care and feeding can save you a lot of hassles and money.

 First, the mic.  When setting up and testing, most people, for some reason, tend to blow into the mic to see if it works.  This is a really bad idea.  The elements in these miniature mics work by physically moving in response to the sound waves created by your voice.  These are incredibly small movements, so the elements must be extremely thin and very sensitive.  Just imagine what blowing on it does; they are simply not designed to handle that much pressure.  Sing a song, say your name, practice your auctioneer skills or do your Little Richard impression – just don’t blow on the mic.  Similarly, when you put the mic on, position the element to the side of your mouth, not directly in front.  In addition to possible mic damage, the heavy breathing is not really pleasant to listen to.

 Next, if you already use a wireless system, look at that wire that connects to the bodypack – pretty flimsy looking, right?  Truth is, it could last a long time.  Almost every week I get a call from someone who needs to replace their mic because the wiring in the cable breaks.  Do not, do not, and do not wind the cable up around the bodypack when you are done.  Don’t roll it up in your hand, or even worse, wad it up to stick it in a drawer.  If you can, disconnect the bodypack and hang the mic and cable so that it hangs straight in a safe place.  I’d be happy to sell you new ones every month, but I doubt you’d be very happy buying them.

 You also need to pay attention to the bodypack itself.  Remember that it is going through the same exercise routine that you are, and probably getting just as sweaty.  Figure that the instructors before and after you are also giving it the same treatment, and you can see the potential for problems.  The best thing is to put your transmitter in a neoprene belt to avoid the possibility of dropping it mid-kick and provide protection from moisture.  If possible, see if you can integrate a ‘drip loop’ as you route the cable to keep sweat from following the cable into the transmitter; if not, try tying a small piece of something absorbent along the cable.  I know of some theater engineers who use art-gum erasers, molded around the connector, to help keep moisture out.  If your pouch or belt is not moisture-resistant, consider using a small plastic sandwich-type bag to protect your transmitter.  Once you put everything on, make sure there is enough slack in the cable to prevent pressure on the connector…and if your transmitter has a flexible antenna, don’t wad it up and cram it into your belt; just let it dangle.

 One more tip regarding the headset: it’s a good idea to gently wash and air-dry the foam windscreen after use.  Although the mic element and windscreen should never be directly in front of the mouth, the screen will still pick up moisture.  Seems like the hygienic thing to do.  Just don’t use a heavily scented detergent – you’ll likely get sick of the smell about ten minutes into the next class.

Now, let’s look at the rest of your sound system.  You will have audio sources (mic and CD player), a mixer, an amplifier and speakers, working in that order.  Your sources connect to the mixer where they can be blended, controlled or “mixed” at what is called line level. Each channel or input will usually have its own EQ, low and hi (or bass and treble), and usually an effects or “aux” control.  If your mixer has built-in effects like echo or delay, this is how you control it.  You’ll probably want to leave these turned down, as effects just tend to make it harder for students to hear in the typical exercise space. Multiple sources can come in, but only one blend of signal comes out. 

 From there, the mixed signal needs to be amplified to a level powerful enough to drive your speakers. The same process happens in your stereo or television at home, you just don’t see the individual steps.  Many facilities are combining some or all of these components to simplify things.  Powered mixers combine the mixer and the amplifier so that all you have to do is connect an un-powered or “passive” speaker (be sure to use speaker cable to connect to your speakers, not guitar cable).  Powered or “active” speakers combine the speakers and the amplifier so that you simply connect the line level, or “main”, output of your mixer to the speaker (in this case, as the output is not powered, you don’t need speaker cable, so regular mic cable or guitar-style audio cable will work).  Active speakers are heavy, so if you plan to lift your speakers onto stands, it may become a hassle.  Finally, portable PA systems combine them all – usually in a rolling package with a handle.  Portable systems are almost always smaller, but much easier to move and require minimal connections and setup.

 Take a minute to consider your needs in a sound system.  Do you need a fixed, permanent installation in a single room?  Or do you need a more portable, easy-to-use system that can quickly be moved down the hall to be used for the incoming spinning class?  Do you also need to use this system by the pool for the water aerobics or swimming class where you need battery power?  We are seeing many facilities choosing the portable PA option, mounting the speakers on collapsible stands.

 Another popular option incorporates a powered mixer, passive speakers and a pair of speaker stands.  Unlike the active speakers, the passive models are relatively lightweight and easy to set-up.  It is important to get speakers and amplifiers that match each other in their power handling.  A mixer/amp rated at 900 watts of power will blow speakers rated to handle 100 watts as soon as someone cranks the volume – and you know someone will.  Conversely, too little power at the amplifier will cause it to work too hard, sound bad and fail prematurely.  We have found that most rooms will need at least 200 watts per speaker for an average class when using music; that translates to an amp advertised as 400 watts (200W per side or speaker) and two speakers rated to handle at least 200 watts continuous.  Remember also that no system (our bodies included) can operate at full capacity for extended periods of time without seriously affecting its performance and life span.  A little extra power lets your system ‘cruise’ at a comfortable pace, saving you money in replacements and repairs down the road. Do you find your mixer turned up above halfway?  You probably need more power. Your product representative can help with this as well.

This is a good place to bring up a few other user issues regarding sound in a fitness environment.  First, overall volume.  Amid increasing complaints and more stringent regulations, a growing number of facilities are monitoring sound levels more closely.  A recent study of fitness clubs by Eugenie Mielczarek of George Mason University found that most are regularly reaching sustained levels of 100 to 120 dB – roughly the same level as a jackhammer close-up.  Think about it this way: 0 dB is your threshold of hearing, 100 dB is ten billion times louder!  Sound dangerous?  It is.  Do your (or your students’) ears ring after a class?  Do you have to turn your car radio up when you leave after a class?  Then you (and your students) are encountering damage. The American Council on Exercise (ACE) recommends 70 to 80 dB for sustained levels, roughly as loud as busy interstate traffic.  At this level, there is enough room to get your mic heard clearly and still feel the music.  Remember that if your music is reaching 105 dB, your voice has to be even louder to be heard.  This brings up the second point: monitoring volume levels not only prevents permanent hearing damage, it saves your voice because you are not yelling over the music.  Relatively inexpensive sound level meters are available from Radio Shack or from manufacturers like Galaxy Audio for $50 to $100.  You may also consider systems that include a feature called ‘ducking’ – when you speak into the mic, the music is automatically lowered a little.  You can adjust this from barely noticeable to pretty dramatic (and annoying).  When used properly, this is handy for keeping the music volume up while avoiding having to scream over it to be heard.
 

Probably the most feared issue in sound reinforcement at any level is feedback. To prevent feedback, make sure you don’t move directly in front of the speakers with your mic.  Feedback occurs when an amplified signal, your voice from your mic and then through the speakers, is picked up through your mic again, amplified again, picked up through the mic again, amplified again…get the idea?  It’s kind of like when you hold a mirror in front of a mirror and the reflection is reflected over and over.  I promise that you don’t want to be standing in front of the speaker in a feedback loop.  Not fun.

 Use good quality alkaline batteries for your wireless system.  It’s amazing how many wireless problems can be solved by simply installing fresh batteries!  We recommend Duracell ProCell professional batteries.  Non-alkaline batteries may not have enough capacity to deliver maximum power to your transmitter, decreasing your range and increasing the likelihood of dropouts.  Rechargeable batteries, while maybe more environmentally friendly, usually have a lower output voltage and just don’t last as long as the alkalines.  If you go with the rechargeables, keep some fresh alkalines around to cover yourself when you need to recharge but still have another class.  Panasonic claims their new Oxyride batteries, to be available soon, will outlast the alkalines.  Keep an eye out for these, too.

 When setting up your system, make all your connections first, turn the mixer volume down second, and turn the power on last.  Connecting speaker cables to the speaker while the amp is on can not only damage the speaker, it’s really unpleasant to listen to.  Same goes for connecting to powered speakers or connecting to the mixer.  Just remember: wherever the amplifier is, turn it on last with the volume down.  Conversely, turn the amplifier off first (with the volume down) when turning off.

 Call other facilities and ask about what they are using; features they like or don’t like, brands or models.  This type of real-life info is perhaps the most valuable. 
 

The fitness environment presents a unique set of issues in the selection and use of audio equipment.  Humidity, vigorous movement and activity, continuous daily use, the wear and tear of constant on and off cycles and the corrosive power of sweat are just a few of built-in hazards facing your equipment.  While modern electronic devices can be amazingly rugged, they still have to be cared for and maintained properly to maximize their service life, and a little bit of knowledge can go a long way here.  Even if you have selected the perfect system for your facility (and now you can), anyone using this equipment should know a little more than simply where the power switch is. A basic understanding of these systems will help you make the right purchases, protect your investment, and at the same time improve the fitness experience for instructor and students alike.