My one-stop shop for wireless microphones has always been www.avnow.com. In full disclosure, I neither represent, nor receive discounts from, this company when I mention their products. On their site, for either 115 volts (USA, some parts of Asia) or 220 (Europe and elsewhere), I recommend the Samson Airline 77 with QE Fitness Headset because it has less parts to need repair from use and sweat. Furthermore, the transmitter is very small, uses one small AAA battery, attaches to the headband, and comes with its own protective clear plastic case to keep the pack dry from sweat. If you must go with a wireless microphone that has a cable that runs down your back connecting into a transmitter pack that usually takes a large 9 volt battery, nestle the transmitter pack inside a non-lubricated prophylactic before placing the pack into a soft, clip-on belt-pack that keeps everything dry regardless of what kind of class you will teach.
· Always LOWER your voice when getting excited while wearing a microphone. This is better for the vocal chords and sounds better to the participants than hearing a high-pitched screaming instructor.
· Keep all decibels lower than 90 including the voice and music.
· If your microphone has a cable running down your back, tuck the cable UNDER the closest article of clothing you are wearing to keep the cable from flapping around in the air when you commence movement.
· Keep the microphone transmitter pack on your back hip, slightly to the side. In this way, you can do abdominals, jump, and even side-planks on the other side and the pack will not injure your spine if you go prone onto the transmitter.
· Extremely low-cost applications for iPhone called “TempoPower”® now lets you electronically pitch-control ANY electronic music stored on your device so your microphoned voice can match the speed of the class you are trying to match.
· Purchase a hard, plastic case in which to carry around your microphone to keep the sensitive parts dry.
· Carry extra windscreens for the ends of your microphone, also available from avnow.com or powermusic.com. The time will come when you will need a dry microphone cover, or want your own cover to put on someone else’s microphone during flu and cold season. You can never, ever have too many of these, and after class, you will find you will often forget to remove your own.