Problems With Wireless Microphones and How to Fix Them

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About: I am an AV and IT guy... I have been involved with sound and lighting since I was 7 yrs old. I currently do Information Technology work for a living, and professional sound as a side job. Although I do bot...

Because there are so many problems that you can have with a wireless microphone system, I have decided to write an instructable on how to troubleshoot wireless systems.  This can apply to other wireless systems besides microphones, but I will be focusing on microphones, since that is what most of my experience is in.

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.

Supplies:

Step 1: Static

This step is taken from my previous instructable "Audio Problems".

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

To fix interference on a mic, you need to adjust the frequency on the mic and receiver to another frequency that is not in use.  (Unless you are a licensed operator that is not restricted by Part 15 of the FCC rules and regulations.)  Consult your owners manual for information on how to change the frequency.  You want to change it at least 2 MHz up or down from where you were having interference.  Mostly, you just have to play with it in order to find what the best frequencies are in your area.  You can also use a wireless frequency analysis program, but those are expensive, and require expensive hardware.

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

Sometimes when you have a microphone that is synced to the receiver via infrared, the microphone will "Magically" change to a different channel, or change a setting.  This doesn't happen often, but it does happen enough to mention.  This is an easy fix, first, find the infrared receiver on the mic (I have mine pictured in this step), then place a small piece of gaff tape over the receiver.  If you need to sync, simply take the gaff tape off and replace when done.

Step 4: Power Off

I can't tell you how often I have had actors/musicians/etc. turn off their power switch for whatever reason, and then forget to turn it back on.  Even when you tell them not to!  Here are two ways to fix this problem:

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

Intermodulation is similar to interference.  Intermodulation happens when you have two microphones or other wireless devices crowding each others frequencies.  The only way to fix this is to change your frequencies to another frequency that is not crowded.  To find frequencies that are not crowded, use an intermodulation analysis program.  One of the best programs available is IAS, however IAS is very expensive.  A free program from Sennheiser is available called "Sennheiser Intermodulation and Frequency Management Software" (AKA SIFM).  It is a very good option if you use Sennheiser microphones, as it already has some of their major models specifications programmed into the software.  You can add other specs in, but you need to know the specs.  I mostly use IAS, so I don't use Sennheiser's software that often, but to the best of my knowledge, you can only use one model at a time with SIFM.

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

The antennas of a wireless system are the most important part.  If you have a damaged antenna, or the placement of the antennas on your receivers are off, then you are going to have some big problems.  Most wireless body-pack transmitters have a little wire coming out of either the top or the bottom of the pack.  Make sure that this is not being stressed in any way, as that can severely damage the wireless signal.  Also, the antennas on the receiver should be tilted at an 90 degree angle if you are using the antennas that are included with your receivers.  You can also get directional and omi-directional external antennas that will significantly improve your wireless range.  If you are using directional antennas, make sure that you have them at least 5 ft apart and that they are aimed so that they cover the whole area you want to cover.  The best case in scenario would be to have them 10 ft. apart, but that can't always happen.

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

One of the most common problems with wireless systems is signal blockage.  Walls, metal, even the human body can affect signals.  There isn't too much you can do about signal blockage, except trying to move your receivers around trying to find a good spot that is not blocked.  Also, make sure that antennas are not touching a person's skin.  The human body acts as an antenna, absorbing signal.

Step 8: Wireless Microphone Brands

One of the most effective ways to get good wireless quality is to get the proper wireless system for your needs.  If you are going to install your system permanently, hire an AV consulting company to come in and do a wireless analysis.  This is the best way to determine what microphones will meet your needs, and in the long run it will save you money.  If you are using a portable setup, make sure to over-compensate for problems you may run into.

I have listed my opinion of various wireless companies below.

Shure:
Pros:
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.
Cons:
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.
Bottom line:
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.

AKG:
Pros:
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.
Cons:
Most of their products will overpower other brands.  Don't buy if you are mixing cheaper brands.
Bottom line:
The best option in my mind.  Just don't use if you are using a Shure or cheaper mic at the same time.

Sennheiser:
Pros:
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.
Cons:
Pricey.
Bottom line:
If you have the money get Sennheisers.

Lectrosonic (thanks to jakdedert for reminding me about this one):
Pros:
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.
Cons:
Pricey.  Probably the most expensive mic out there.
Bottom line:
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.

Audio Technica:
Pros:
Good mic.  Nice user interface.  Better wireless quality than Shure.  Holds up to professional use.  Decent price.
Cons:
Not as good sound quality as Shure.
Bottom line:
Not a bad mic for those who are on a budget.

Line 6:
Pros:
Decent digital systems for the money.
Cons:
Not as good as Shure for the digital.
Bottom line:
Good entry level digital system.

Nady:
Pros:
None.
Cons:
Terrible wireless mics.
Bottom line:
Don't buy nadys wireless products.

VocoPro:
Pros:
You get lots of mics
Cons:
Very prone to frequency crowding, and there's nothing you can do about it since they are fixed frequency.  Terrible sound quality.
Bottom line:
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

Please note that I do claim copyright to the information. I did not use any specific sources when compiling this information, all of this is from my personal experience.

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.

© 2012

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    31 Discussions

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    brianm9943Prescott

    Question 2 months ago on Step 8

    We have 4 wireless microphones with their own receivers. They worked fine for 15 years. Then one day last December, all 4 of them started acting like the transmitters are out of range (intermittent buzzing/static) when we move to the front of the room or move around. It's fine if we are near the receivers. Nothing (that we know of) has been changed. We had done a radio drama earlier that week and had unplugged some things from the mixer and plugged them back in later. At first I thought an antenna was broken. In a previous location, that's how the system would act if the person with the transmitter went outside the building (out of range). But all 4 are doing it, and two are handheld wireless with internal antennas. I checked the frequencies and they are not in the range which can no longer be used. HELP!

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    hkh141995

    Question 2 months ago

    i have 2 set of ahuja 490 vhl mic system,both frequencies are interfering with themselves please help me to resolve this problem

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    Hawk-2479

    Question 4 months ago on Step 1

    Static didn't occur until a Deacon wore a wool vest under his garments and the mic cord was between Vest and Garment. Could static still be in the wires and possibly removed with Bounce dryer sheet that is anti static?

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    Nkashama

    4 months ago

    Hi bro I hope you are well, I'm having problem with one of my wireless microphone, actually it switches on , but is unable to produce sound to the mixer and speaker , no sound comes out even tho it is on and the signal range in pla

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    Kjoy88

    Question 6 months ago on Step 8

    We have the VocoPro 4005 microphone system in our church. It’s a 4 channel system. We just bought it and already have had to warranty it out and replace it for the same issues. The sound keeps dropping or coming in and out on random microphones. This happens without fail every service, which is very frustrating... The receiver is approximately 10-12 feet away from the mixer, which is a Mackie Pro FX 12. All of the microphones are within 15 feet of the receiver. Is there something you could shed some light on to stop the sound from dropping?

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    Henry the 9th

    Question 1 year ago

    I have a cheaper wireless mix for a my dj service and when you turn the mix on and off it has some weird noise that sounds like a power surg and the mix cuts out I have it plugged into my amp that has 2 microphone imputs

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    I just bought a new shure wireless lent it 2 a dj and it rolled off dj booth have a dent in it now it cuts out i have 2 play 2nite is there something i can do 2 fix it

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    jze

    5 years ago on Introduction

    Hi there, i've been given a field recording which seem to have audio glitches on it. the glitches are not a click but a short burst of noise, like someone rub or brushes against the mic. According to the recordist, nothing of that sort happen. Do you have an idea where it comes from? Could it be that the frequencies on the wireless system are relatively close to another?

    3 replies
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    JohnP427jze

    Reply 2 years ago

    I have the exact same issue with my GLXD BETA87A. When I yell it makes a short load burst of white noise. Does anyone know what this is?

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    Carmie05JohnP427

    Reply 1 year ago

    That definitely sounds like interference. You probably want to scan for a cleaner channel and/or raise your squelch level on the receiver. Squelch is a function that blocks out any RF that falls below a certain level. If you want a little more info I have an article on my blog you will want to check out. Also email me if you have any questions. Carmie05@aol.com https://avninjablog.wordpress.com/2017/08/01/8-useful-tips-for-handling-wireless-mics/

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    FireAce4JohnP427

    Reply 2 years ago

    Shure just released a firmware update for the GLXD system. I gave them a hand in testing it before it was released a couple weeks ago. It should fix this issue.

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    JosephC273

    1 year ago

    I have Sennheiser Radio mic belt pack EW100.

    Every now and again (about 10min) I get a spike.

    What causes it and how can I stop it from happening?

    Kind Regards

    Joe

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    rokknrob

    2 years ago

    Hi, I had two wireless AKG mics that were 15 years old so I bought two Samson concert 88 dynamic wireless mics. for a karaoke system set up permanently in a bar setting. Two fifteen in JBL and two 10 inch JBL speakers. System sounds great and the mics blow away the AKG's. The small problem I have is that now with the two new mics I have a (for lack of a better word) SNAP sound when certain people use one of the mics. It is intermitten. Maybe two or three snaps during a song and only on certain singers it seems.They are 16 channel true diversity mics. I haven't tried changing the freq. yet. the Freqs. are 0 thru 8 and A thru H. I have one mic on 0 and the other on F. Is there a reason I would get a snap on a new mic? I guess you could call it a (crack) too. Any information would be appreciated.

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    rohit_puri50

    2 years ago

    Hi, I bought "Soulo Digital Wireless Mic", it comes with a 30 pin connector, which connects the mic with the device for the sound output. But i am unable to connect the wireless mic with the connector (which i have connected with the phone or iPad). can anyone help

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    DavidP151

    3 years ago

    i have a problem we have a lower end set of wireless microphones and one day the reciever just stopped picking up the mics

    Hi, I work for a low budget church and suddenly find myself responsible for a sound system I do not completely understand yet. One of our handheld wireless mics suddenly sounds "tinny", like there is no bass in people's voices. I don't know if this is a setting on the transmitter (nobody has touched it or changed it) Or if something has "blown out" in the mic and we just need to replace it. Looking it up I see that will cost us $250 to replace it and we have to be careful with money but I would also like to figure it out myself, because if we call in the sound technicians it will cost us more.

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    gluvit

    5 years ago

    Helpfull

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    Rgamer1

    5 years ago on Introduction

    Hi
    I have an issue with the microphone set that is pictured above. The other day I was running the sound board for church. While I was running this only the clip on mics were being used. I look down to see if the next speaker has a turned their mic on for the next part. I then realize that the hand-held mic has a one dot on the signal bar. I thought "Strange what is causing this" because normally it would show all dots for the best strength. I go get the hand-held mic which was put away and I notice that it was off. This was really weird. We turned the receiver for that mic off and then back on and it seems to be fine. You seem to be the only person who would know this so far in all my searching for the issue. Do you think this might be interference with the other mics or is it showing its weaknesses since we have had it for ten years?

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    tekdva

    5 years ago on Introduction

    Good information.
    We have the same AKG handheld as pictured above and the battery won't stay in place. Even with the battery cover on, the battery keeps popping out, which turns the mic off. Any suggestions?
    Thanks!

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    rosiehall

    5 years ago on Step 8

    have you worked with capture before? its giving me major difficulty