Behind The Mixer

Learn Church Audio Artistry | Church Sound

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Track Down The Buzz In Your Sound System

Time to can the buzz and move on.
Photo provided by ctoverdrive

Buzz in an audio system might be the most annoying sound you’ll ever hear.  A close second is the first unexplainable rattle emanating from your new car.  Buzzy audio has been the source of many an email I’ve received and today you’ll learn the process for tracking down that audio buzz and stopping it.

Audio system noise comes from a variety of sources.  These sources include;

  • Bad gain structure: If you aren’t providing a high signal-to-noise ratio then that noise could be typical line noise from a mixer channel.
  • Crossed cables: Any time an unbalanced cable is run in parallel with an electrical cable, then the audio cable will pick up interference.
  • Ground loop hum: Noise from the building’s AC power lines which are attached to your system.  Caused when more than one piece of equipment in the sound system is connected to a common ground through different paths, like different electrical outlets on the same circuit.
  • Problem buzz: Buzz that’s produced as an indication of failing equipment, failed equipment, or improperly connected equipment.

It’s that last one which is covered in this article.

The first step in stopping audio buzz

The first step you should take in tracking down the source of buzz is determining where the sound is emanating.  There are four primary areas where buzz can emanate;

  1. House Speakers
  2. Stage Monitors
  3. In-ear-monitors: You’ll hear the buzz in the house or the stage monitors but you’d hear a musician tell you there is buzz in their in-ears.
  4. Recording: In this case, you hear the buzz when you listen to your recording of the service.

Tracking down buzz, in-ears and recordings aside, start by turning down the house volume.  If you still hear it, it’s coming exclusively from the monitors.  Otherwise it’s in the house or the house as well as the monitors.  A simple test for monitors is asking a musician to listen to the monitors when the band is quiet.

Audio is routed through your system in many different ways and therefore, when you know where the buzz is emanating, you can focus on the signal chain for that particular output.

Locating the general source of the buzz

Ask the band be quiet.  Then, either boost the monitor or the house volume depending on where the buzz is emanating.  Next, mute your channels one-by-one.  Dealing with a house-speaker buzz, you should be able to find the offending channel if it is a channel-specific problem.  Dealing with monitor-specific buzz, make sure your channel aux sends are set to post-fader so when you mute the channel, you are also muting the monitor aux send.

Find the specific source of the buzz

Let’s pick on the ‘lectric guitar because they have the most gear on the stage.  Going through the above process, let’s say when you mute the electric guitarist’s channel that the buzz goes away.  Looking at the signal path from the guitar to the mixer, you have*;

  1. The electric guitar
  2. The guitar’s output cable
  3. The effects pedals or single-unit effects box
  4. The associated cables with the pedals / the cable coming out of the processing units
  5. The direct box for turning that unbalanced cable into a balanced cable for the long run to the sound booth
  6. The cable from the direct box into the stage jack
  7. The stage jack cabling either into a snake or directly to the sound booth

*The above can be more complex if they run through an amplifier on the stage.  Make a note if they do and adjust your definition of their signal path accordingly.

Start with the area that’s most likely to cause the buzz; the cable into the electric guitar.  Ask the guitarist to unplug that cable and plug it back in.  Often, it wasn’t fully plugged in and this will solve the problem.

Next, ask them to plug their guitar directly into the direct box.  You will be bypassing their added equipment and will quickly find out if the buzz is or isn’t from their processing units.  If the buzz goes away, ask them to re-seat all the plugs in their pedals and try again.  If the buzz didn’t go away when they plugged into the DI box then have them flip the ground-lift switch.  If the buzz goes away, you know it was a grounding issue either caused by ground loop hum or an instrument grounding problem which you can later investigate.

Let’s say the link from the guitar to the direct box still produces buzz in the line.  Swap the guitar cable for another one.  Still a problem?  Swap the cable from the DI to the stage jack.  Still a problem? Oh, such is the life of a sound tech!  Swap direct boxes.

Whenever you have buzz that’s coming from a particular channel, you have two possibilities; anything coming into that channel or, the channel itself.  You can figure out how to run out all the possibilities on the stage.  The key is swapping out gear until you find the source of the problem.

Back in my radio days, one Sunday afternoon, the station was broadcasting a live NFL game for the Indianapolis Colts.  We had a cable patch bay for routing the satellite signals to the broadcast booth.  I had to completely crank the volume on the broadcasting mixer to get any decent volume from the satellite.  Bad cables can produce a variety of results, from no sound to low sound to buzzy sound.

Channel problems?

You might have channel problems on the board.  A quick way to test this is by swapping the input cable from that channel into a different channel that’s functioning correctly.  Also, be aware of any rack equipment you have plugged into a specific channel.  These could be compressors or effects units for example.  Unplug those to remove them from the signal chain and listen for the buzz to go away.

What if it’s not channel related?

The good news is buzz that appears today that wasn’t their yesterday, is probably channel-related.  The reason is moving parts.  For example, plugging in a guitar cable puts wear and tear on the components.  The more wear and tear, the more likely to wear out.  That being said, all equipment eventually fails.

Buzz coming out of the system, which isn’t created before it enters the mixer, means you likely have equipment failure of the expensive nature.  Yeah, sorry about that.  It’s possible a cable has gone bad or equipment was bumped which pulled out a plug part-way.  But, well, ummm, one can only hope it’s that cheap and easy.

Back to finding the source

Tracing the signal flow for a simple setup, the sound goes from the mixer into a house EQ then into a limiter then into the amplifier and then out to the speakers.  Cross your fingers, say a prayer, and start by checking all cables are properly seated in the signal path.  Turn off the power before you start re-seating cables.

From here, start swapping cables.  Of course, make sure everything is turned off before you do anything.  You are a bit limited in what equipment you can swap unless you have spares of everything or can pull from another system.  Consider bypassing the house EQ and then the limiter.  I’d bet dollars-to-doughnuts that the problems won’t go away and that it’s in the mixer, but you just never know.  Also, I have never bet dollars-to-doughnuts because I’m not usually flush with doughnuts.

Equipment Repairs

There are obviously many ways equipment and cables can fail.  There are two questions you must then ask yourself;

  1. Do we fix it or replace it?
  2. Where will we find the money?

Regarding the second question, I could easily spin off into talking about budgets but I’ll keep it short with these few bits for your consideration;

  • You should have an annual budget which accounts for possible equipment replacement.  Don’t worry about a total cost replacement but a 30%-50% replacement amount would be good.
  • Your audio budget should include a plan for general replacements/upgrades.  For example, in 5 years, when you plan on upgrading the speakers, you’ll want to have already set aside the money.

Fixing versus replacing isn’t a question of which is cheaper, it’s a question of what makes more sense.  For example, if it would cost $500 to fix your $1000 mixer, it might be the time to go ahead and get that mixer upgrade you’ve wanted.  However, if it only costs $150 to fix it, then just fix it.   Cables can be replaced or repaired at little cost.  Do what makes sense.  As well as being the person in control of the audio system, you are also to be a good steward of money.

The Take Away

Audio buzz usually comes from only a handful of places like; equipment, instruments, and cables.  The key to tracking down the source of the buzz is identifying the output and the general source.  Then, narrow that focus and find the specific source.  It’s detective work and you have to follow the clues.

Finally, signal-related problems such as this are covered in the Line Check chapter in my Audio Essentials for Church Sound guide.  You can learn how to quickly diagnose and resolve signal problems.

 

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Comments

  1. Hi Chris,I just want to 🙏 thank you!! Your web site was so informative. First of all I am computer illiterate and not savvy with my equipment and solving problems. I am a retired piano- player -singer who had a great fun career in the music business. In January I lost my best friend and her husband unexpectedly, I was shattered with this loss. The family is having a memorial service in May and have asked me to sing. My system started buzzing through my speakers and I wasn’t able to use it!! I found your website and I was able to fix the problem. You saved me a lot of grief in trying to get it fixed before the service so 🙏 again, Thank You, Christine 🦋

    Reply

  2. Hi Chris,
    I came upon your website while troubleshooting a strange, sudden, temporary loud buzzing problem involving my mixer and keyboard. I have a small, home studio recording setup: An A&H (Allen & Heath) analog mixer, a Kurzweil PC2/X keyboard, a laptop audio interface, and a few Mic preamps. These are connected to various channel strips in the A&H. The output of the mixer is connected to powered monitors.

    The problem is only occurring in whatever channel strips the Kurzweil is connected to – I’ve swapped it to other A&H channel strips to confirm that. The Kurzweil connects via its balanced L/R audio outputs to two channel strips in the A&H.

    Buzz problem description: It happens randomly and the sound suddenly rises to full loudness, meters and channel lights in full, red overload, and can only be stopped by muting the 2 keyboard connected channel strips, or totally turning down the main output level. The loud buzz only lasts for about 10-15 seconds, then disappears. It returns for about 2 or 3 seconds, then everything is back to normal. The keyboard sounds are fine, and no audio is affected. Now, these buzzing episodes may return 10 minutes later, an hour later, or not for the rest of the day. Other times, I can go all day with the keyboard channel strips on, and there’s no problem. When this occurs, the buzzing is so loud, I have to cut it off as quickly as possible so it doesn’t damage my monitors in any way.

    The keyboard and all its sounds/voices seem perfectly normal. And this problem never occurs with any other equipment connected to the A&H mixer. It’s a mystery, and has only started a few months back. Maybe you have some expertise on this or some thoughts as to what’s happening. Thanks, in advance.

    Regards, David

    Reply

  3. Hi Chris,
    Stumbled upon this article while searching for a solution to the humming noise im getting through my mixer.
    i have a set up of a xone mixer with 2 x technics 12010 and 2 x rokit speakers, now with nothing else plugged into the mixer (and ive tried plugging it in every room in the house) im getting a dull humming noise and i cant get rid of it! any suggestions?

    Regards, Ryan

    Reply

    • Look for anywhere you might have accidentally run an unbalanced cable next to a power cable. Would be a good place to start. Also see if any output gains were increased.

      Reply

  4. We moved into a relatively new building a year ago. From day one, I have buzz in my system just from turning the system on, with no channels on, just powering up board and speakers. I have found out that this has been a problem from the day the snake and stage wiring was installed. I have chased this problem all down the line and have reach a point that I have only one other idea. That is that possibly the snake is running down steel pulsing along side one of the power service feeds. If this is the case, is there any way to shield the snake from this?

    Reply

    • Do you hear it in the main speakers or the monitors? Are the main/monitor speakers powered or non-powered? I’d try running a few cables in a separate area – just to test, and only use those cables. See if the hum is gone. If it does disappear, then you’ll likely need to move the snake or power lines…unless it happens to be a problem with the amp.

      Reply

        • That sounds like a problem in the cabling form the sound booth to the speakers. Can you run a cable directly to your speakers from the sound booth, as in across the middle of the room – obviously not during a service. If the buzz is gone, it’s either in the cable or the cable is running next to an electrical line.

          Reply

  5. Resolved….sort of. Replaced the laptop with a desktop- buzz, hiss and crackle are gone, pure silence when nothing is running or playing on the system, plugged into the same outlet as the laptop had been, hooked up with the same cables as the laptop had been. I don’t get it, but silence is golden, and I am happy. Thanks all!

    Reply

  6. Hello Chris,
    Thank you for very useful article. But I have one question. How to know if noise I hear is a sign of failure or it is just a normal working noise. I have a PM2000 and it makes some buzzing noise even if all channels turned to zero. It is enough to turn the main level half way and buzzing became annoying. I have checked it in two different locations and it was the same. But it fluctuates. Some times it is louder, some time – quitter. I assume the mixer is failing and is going to buy another one, but I am in doubt. What if it is normal for mixers and the new $500 one will do the same?
    Also, is it possible to ask you for an advise on what to buy if I will decide to upgrade my system? If so I will be glad to provide you will all necessary specifics.
    Thank you,
    Lev Tannen

    Reply

    • Do you have a powered speaker you can run to the mixer, bypassing the amp. It could be the amp that’s causing problems. I’ve known more amps than mixers that have shown problems with age.

      Reply

  7. Hello Chris,
    I have a small Mackie mixer (3 inputs, 2 pin original power supply) connected to Peavey amplified speakers.
    SM58 (7 feet cable) not gives any hum.
    But when connect Lenovo tablet with (2 feet audio cable) it gives a noticeable hum when rasing a volume.
    Read many articles… but didn’t find any about tablet. All of them say short cable is a solution.
    I have only 2 feets. Any suggestion.
    Thanks.

    Reply

    • Make sure the volume on the tablet is turned all the way up. Then the cable coming out of the tablet is a stereo cable, right? if so, then it needs to have one end split into two RCA jacks for the left/right signal and plug those into a stereo channel. Or, the stereo cable needs to go into a stereo AV DI box that sums the stereo into a balanced mono signal that you can plug into the channel. A mono channel strip takes in balanced mono signals. When you try to pass a stereo signal in, it might work with hum, it might give weird sounds, or it might not work at all.

      Reply

      • Just for fun tried couple of SmartPhones. Connected LG – the same effect as a tablet (Lenovo).
        As a last resort connect old Samsung. It is quiet like a baby. Even on max master and channel only high freqs noise present that is absolutely normal. But no hum. Used the same cables.
        From this I can conclude that the device matter… Will try tomorrow other tablet and cell brand.
        Sure don’t want to add DI… I will better try to switch may be to digital mixer. But the prob is with a short 1/8 cable on a tablet… The noise starts at a particular volume level. During playback it is not noticeable at all but when stop in 3-4 seconds it takes off. Really strange effect. What is weird that power supply is without ground pin. I even tried to cut a ground pin from the speaker power cable for a test. No help. Come to conclusion that some brands doing something special to avoid the problem (Samsung has 0 issue).
        Thanks for your answer. If I will succed to find other “clean” brand I will let know.

        Reply

        • Hi Chris,
          I tried 2 other devices… Acer tablet and Acer SmartPhone. The same player – RocketPlayer, the same cables. Works just fine. Cristal clear sound with absolutely no hum when playback stopped.
          Ooofff… Problem solved. The conclusion: Device Matters :).
          It is possible to find a tablet not creating any noise on out through the mixer.
          Thanks for your blog…
          Michael.

          Reply

  8. Hi. Should the fan in my sound board always run? If it doesn’t, will that cause the sound board too not function properly?

    Reply

  9. Hello. I am runing a bass through the PA. That part works fine. Sounds really good through the main speakers. Nice and balanced. But when I use my in ear-bud monitor so I can hear the bass there is a constant hum. I was plugging the bass directly into the mixer using a unbalanced guitar cable. I then run the mixer output for monitors into the In ear monitor processor. I have no trouble with vocals or acoustic guitar through the in ear monitor. Is this a grounding issue? I tried using a balanced cable but that didn’t help. Should I use a DI box that has a ground switch to see if that helps? I did swap out cables using both unbalanced and balanced cables with the same results. Any advice? Thanks

    Reply

    • The bass should go to a passive DI on stage. Make sure the instrument cable from the bass isn’t running parallel to a power cord. This should also be a cable run of under 15 feet. Then you should have the XLR going from the stage to the mixer. Make sure the volume on the bass is turned all the way up. Also, if the bass isn’t plugged into the mixer, do you still get the hum? Make the sure problem really is with the bass and not something else.

      Reply

  10. Hi, I have a laptop connected by a standard small headphone jack into the mixer for a small school/church. We had to swap out the laptop, which would occasionally produce very low white noise, with a different one which produces a significant amount of crackle and buzz. I discovered that if I unplug the power cord to the laptop, the noise goes away immediately. There is only one power source in the sound booth, and the sound board is already plugged into that outlet, as was the previous laptop which had limited hum. Is there a connector that could be purchased that would limit or insulate that cord from other white noise from the sound board?

    Reply

  11. Hi, I’m the drummer at my church (small one). I just bought a pair of Sure ear buds. When I plug them into the monitor output jack directly on the stage, I can hear ok(on a setting of 4-5/10) but there is a pretty significant buzz. Is it ok to use these ear buds this way or is that too much signal to go direct like that?
    thanks

    Reply

      • Hi Chris, thanks for the reply. I mis-labeled the noise as a buzz but it is really more of a “hiss”. They go through a 3.5 patch cord to a 3.5/1/4 adapter on a 1/4 patch cord which plugs into the 1/4 socket on the stage. (what is a DI?) I do know that the monitors do have an amp so I think that would make them powered? I also found out that I can turn the main monitor down to 2/10 and still hear ok.

        Reply

  12. I am attempting to setup an in-ear system for our church. I am using this web link as my source for what I am trying to do. https://collaborateworship.com/in-ears/

    The problem is that we are getting a buzz. Now I am coming out of a speakon jack into the splitter 6. When the speakon is plugged into the regular floor wedge monitor, there is no buzz. I purchased a cable that has the speakon on one end and the XLR on the other to go into the Splitter 6. I have tried 2 different cables but still getting the buzz. Any suggestions?

    Reply

    • Is that a powdered/active monitor or passive? If it’s a powered monitor, then that’s good. However, if it’s not a powered monitor then that means you’re sending a speaker-level signal to the floor monitor – which is what you should do for a passive monitor, but it’s not the right level (too hot) for your rolls amps.

      Reply

  13. Hi guys / gals!

    Our church is getting a buzz / noise coming when we run a live worship for broadcast. I’m sure it’s coming into the CD recording as well (I’m new to running sound for this church so I’m still getting used to how their setup is). Our main concern is the live broadcast with CD recording being secondary.

    There doesn’t seem to be any noise coming from the sound system or the instruments, so I”m not sure where it’s coming from.

    To my knowledge, they’re running the cable directly from the board (stereo adapter to RCA) to a laptop and it’s combining both the audio and the video simultaneously via RCA and a Roxio Video Capture USB. It is running directly behind the rack system so i’m not sure if that could be it. We are using an analog Mackie and using extensions from the board to the laptop. My theory is how the line out is running (behind the rack system) and / or the fact that they are using extensions from the board to the laptop and possibly the USB capture hardware.

    If it could be the RCA cables or the adapters, we need to have the adapters but the RCA cable would have to be around 20 feet long in order to reach and we’d still need the adapters. Would you suggest a different kind of cable and adapters / connection from the board to the laptop?

    Any assistance on where to start and if I could use you as a resource as we track/resolve the issue, is appreciated. Unfortunately, since I am so new, I don’t have full access to the church (i.e. key access) so it’s only when church and the head tech is available (who knows how the system is setup but not really an “audio guy” in his words).

    By the way, I used a lot of what is on this site and the download with my previous church and it helped immensely but I’m no where near being a professional or fully proficient on audio. Thanks!

    Reply

    • It could be two things. First, it could be the distance of the RCA cables. If they are running parallel to power cords, that would do it. Also, I’ve experienced buzzing in windows computers when the audio drivers didn’t work well with the software. You’d need to look for windows drivers specifically for that software and then research how to configure them for input devices.

      Reply

  14. Hi, I just installed some track lights over our stage with a dimmer switch. Every time I turn those track lights on , we get the buzz sound .the brighter the light dimmer, the higher the buzz.

    Reply

  15. I Hear A Static Sound Like “Shshshshshshshsh” But Load When I Highen Or Lower Sound Volume From My Tall And Thin Speaker!Its small!It Doesn’t Produce Any Sound Doesn’t Matter What Sound Level Is!How Do I Get Rid Of That Static Sound?Shshshshshshshshsh!How?Plz Help Me I need Sound Very Much!!!

    Reply

    • Could be from a number of things. Start by muting all of the channels. If it goes away when you mute a channel, check out that signal path to find the cause. If it’s still present when everything muted, turn off your system and check all of your cabling and power connections. Unplug them and re-seat them. If it only happens when you raise or lower your volume via the console, it could be the console. Maybe the amp, amps can do weird things. You have to check every path by turning off (eliminating) other potential areas so you can pinpoint the cause.

      Reply

  17. Hi. I work at a Christian Camp in Colorado. I just installed a new sound system and am experiencing Ground Loop Hum. All my available outlets are on the same circuit. How do I get rid of the hum?

    Reply

  19. Most of the mixing I do is at a 3 seasons camp my church purchased about 5 years ago, which used to be owned by the Nazarenes here in Iowa. Apparently the Nazarenes are big about getting the most “bang for your buck” and stretching a dollar as far as it can possibly go, leaving us with some pretty fun power issues, one of which was no power to the stage. Oh, except for that one outlet that worked maybe half the time and we never used it just in case it might blow something up…..So after a few years of running our entire system off of 2 circuits (I’d like to take a moment to say that whoever came up with multi-outlet power cords was a genius), we finally had an electrician come in to give us direct power to the stage. It kind of solved the problem, but almost every time we go in there for a conference or large event there is some kind of buzz or hum coming from one of the monitors generally due to a grounding issue. I usually just raise the ground, but it’s not always on the monitor that’s buzzing so the trick is coming up with the right combination to get rid of the buzz.

    We did have an issue once where, during tear down, if you unplugged from one of the monitor channels on the snake it would produce an awesome system buzz (like a 40 lb bee in a can with lots of reverb). Turns out the ground pin on the power to our FOH rack had fallen off causing the snake to turn into an electrical ground instead of audio ground. That’s when I learned how to repair the ends of power cords :-)

    Reply

  21. A mechanic friend of mine taught me the first law of troubleshooting anything — check the cheapest part first. Then the cheapest remaining part until you find the problem. The least expensive items are usually the most likely to fail in any system, electronic or mechanical.

    Reply

    • Bill, that’s a great point. Murphy’s law would say start with the most expensive! Your friend is right, most of the time it comes down to the smallest of things.

      Reply

  22. In our church we have two services at the same time (different languages) and one morning I entered the main auditorium where guys were setting things for their service and there there was some feedback with no microphone open. My first guess was ‘induction loop’. When we switched the loop amp off the feedback disappeared. Loop and (unbalanced?) audio cables were too close probably.

    Reply

  23. We just finished replacing the electronics in a bass to get rid of a hum, some internal grounding issue where the hum only happened when not touching the strings.

    Secondly, this article couldn’t come at a better time- Christmas lights! Every year we get a pronounced hum at multiples of 50hz (uk power) because there are lights on the Christmas tree very close to the stage. Thankfully we can notch the eq quite tightly around those frequencies.

    Lastly, I spent ages trying to track down a whine – especially when complaints started arising… After eliminating every component (the system was effectively off by this point), the whine remained! Turns out it was a hearing aid.

    Do you have any articles on hearing loops by the way? Our loop amp is cranked all the way up but I have no way of knowing any differently.

    Reply

    • You get 15 minutes? LOL. Yeah, I always taught my team to have at least 15 minutes between when you are done and when the service starts. It means 1) people don’t see us running around in a panic and 2) gives us time to walk around in a panic.

      Reply

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