If I miss anything, or you would like me to add something to this instructable, please let me know. Also, if you are having problems that are not wireless related, please see my instructable "Audio Problems", or feel free to contact me for help.
Please keep in mind that I can only cover a few problems you can run into with wireless. I will only cover the basics in this instructable.
Step 1: Static
Static on a wireless mic is usually caused when the mic is too far away from the receiver, a battery is dieing, or when something is interfering with the signal. We will cover interference in another step. Often the simplest way to resolve static is to change the battery, or to get the mic closer to the receiver.
A good way to get the mic closer to the receiver is to move the receivers to an area backstage or onstage. Many facilities already have wire run from their backstage or onstage areas to their tech booth. This is generally considered the "correct" way to use a wireless microphone system.
Step 2: Interference
Digital microphones use about a tenth of the bandwidth that an analog mic does, but with some of the cheaper digital mics, you can run into problems with a high latency. (High latency is when there is a noticeable delay between when the person speaks and when the sound system produces the audio... latency is the time it takes for the signal to travel from the source to the destination.) The reason digital mics have a high latency is that audio is basically analog. Digital mics have to convert an analog signal into digital, then convert that digital signal into analog. Not to mention that they will select the channel with the least attenuation. Granted, this processing takes milliseconds, but add enough milliseconds together, and you will have a noticeable delay. Most of the major manufactures have fixed this problem in recent years.
Step 3: Channels "Mysteriously" Changing
Step 4: Power Off
1. Most microphones have a power lock. This will keep the mic on, even if it is switched off. This is the most effective way. The only way to turn it off is to know how to remove the power lock, or to remove the battery once you turn the power lock on. Refer to your owner's manual to see if your mic has power lock, and how to turn it on. Since Shure ULX is one of the most popular mics, I will tell you the process for that one. Press set, then mode together (set has to be pressed first) until you see Po L on the screen. It is now power locked. Generally most mics (including Shure ULX) use the same key-combination in order to unlock that they did to lock.
2. Place a piece of gaff tape or medical tape over the power switch. Most people will not remove tape for fear of breaking the mic, and it also protects from accidentally bumping the switch off.
Step 5: Intermodulation
Also, frequency crowding is caused when you are using too many mics at the same time. Generally, you can only use about 16 analog mics at the same time before you start to have frequency crowding issues, however, if you use a program like IAS, and depending on the area you are located, you should be able to get as many as 22 analog mics. If you need more than 16 mics, than you should go with a digital system. As I mentioned before, digital mics only use about a tenth of the bandwidth of analog mics, so you should be able to use about ten times the number mics you could use if you are using analog.
Step 6: Antenna Problems
Any fixed frequency microphone will have an antenna that has a specific length. You can not change the length, or it will not work well. If your antenna on a fixed frequency mic goes bad, then you have to get the exact same antenna from the manufacture if you are going to fix it yourself. Otherwise, get a new mic, or send the mic in for service.
Step 7: Signal Blockage
Step 8: Wireless Microphone Brands
I have listed my opinion of various wireless companies below.
Name brand company, almost everyone has heard of Shure. Their cheaper products are good for some applications. They have somewhat decent sound quality. Easy to use interface. Very good digital products.
Products made very cheaply, do not hold up well to professional use. Their analog systems are prone to wireless interference more so than some other brands. Will not hold up for a portable system.
If you are on a budget and don't need a lot of mics, get one of their cheaper products. Also, their digital products are very good, so if you are going digital, Shure mics might be a good way to go. Don't buy for portable systems.
Good sound quality. Name brand. Reasonable price. Very powerful. Easy to use. Holds up to wear and tear. Good for portable systems. Not bad for installed systems.
Most of their products will overpower other brands. Don't buy if you are mixing cheaper brands.
The best option in my mind. Just don't use if you are using a Shure or cheaper mic at the same time.
Fantastic sound quality. Name Brand. Best wireless quality between AKG and Shure. Easy to use. Holds up to wear and tear. Great for all systems.
If you have the money get Sennheisers.
Lectrosonic (thanks to jakdedert for reminding me about this one):
Fantastic sound quality. Name Brand. Considered to have the best quality of any company. Easy to use. Holds up to wear and tear. Great for any system.
Pricey. Probably the most expensive mic out there.
These mics are mostly used in video production and for productions with an unlimited budget. If you can afford a Lectrosonic, then there is no doubt that it is the right mic for you.
Good mic. Nice user interface. Better wireless quality than Shure. Holds up to professional use. Decent price.
Not as good sound quality as Shure.
Not a bad mic for those who are on a budget.
Decent digital systems for the money.
Not as good as Shure for the digital.
Good entry level digital system.
Terrible wireless mics.
Don't buy nadys wireless products.
You get lots of mics
Very prone to frequency crowding, and there's nothing you can do about it since they are fixed frequency. Terrible sound quality.
OK if you don't expect to use all the mics at once and are on an extreme budget.
There are other brands out there, but these are the ones you will see most often. If you have a question about a specific brand, please feel free to ask me.
Step 9: Copyright
You may quote parts of this information for educational purposes. Under no circumstances will you sell this information.
I do not own the copyright to the of the images in the introduction steps 1-2, and 4-8, however, as far as I have been able to find, I have the right to use it in this instructable. If there is any question about whether or not I have the right to use this image, please contact me. I have no intention of stealing anyone's intellectual property. I do claim copyright to the image on step 3.
For further information on copyright, please see the license agreement to the right.
Use of this information implies that you agree to these copyright terms.