Understanding and Fixing Ground Loops in Live Sound

[@samuraijaydee]

Wow, what a great video. That was very concise, technical information, with practical examples. You've a great sense of humor. Subscribed!

[@JBMAGNUM876]

This is a perfectly detailed and informative presentation! We'll done and thanks for sharing 👍🏾

[@vittoriaeterna]

This is an EXCELLENT video. David Wills is a mastermind.

[@bobfunk5055]

Stuck tongue in toaster, hum went away, it works !

[@sdriza]

thanks - we have a show tonight, will try that

[@BasementBerean]

2:00 The green ground wire in a standard USA 120V residential electrical system goes back to the same place (the neutral bus bar in the circuit breaker box) as the neutral wire. The "ground" wire provides a second, fail safe route back there in case of a short within the AC powered device. You might say that the "ground" wire prevents a human from being the ground in case a short within a device occurs and the outside of the device goes hot and a person touches it, causing the current to go through them, and the ground, to find it's way "home" so to speak. But, the ground (green) wire goes back to the breaker box and attaches to the neutral bus. That neutral bus bar in the circuit breaker box is grounded (for lightning strikes), but people saying, or giving me the impression, that the "ground" wire goes into the ground has kept me from understanding how AC really works until I recently really had to learn for myself.

[@patricklouie7737]

Actually, it differs from country to country. In Europe, for example, you have a grounding system called TT, which stands for Terra, Terra, or Earth, Earth, and you have TN systems, Terra Neutral. In TN, you use the neutral for your grounding conductor, which seems to be what the US does, and then you add additional grounding to lower the resistance, and for lightning strikes, to go straight to the ground, which means that your transformer station is also grounded. Here's how it works. At your transformer station, you take a center tap from where the voltage equals zero between the potential differences, depending on how many phases the transformer are, and then they run a thick cable out into the graph and spike down a lot of stakes, depending on how big the transformer is and other things. This creates a path through the earth with high impedance for any faults to run back to the transformer, because electrical circuits always want to go back to their neutral point, in this case, the transformer's center. When you use the neutral as a ground, you have a very low impedance, but that doesn't mean that the current doesn't still run to ground, because if it didn't, you wouldn't be electrocuted by touching just one of the outputs, for example, the hot wire. Very easy to test, you could just use a secondary transformer as a output, even if it's still 110 volts, you won't get shocked on one wire, because you now have no reference to the ground. Take a center tap, and take another center tap, and you can see that the current is still running Take a center tap, and take an earth rod, and bang it into the earth, and now touch the output, and I guarantee you will be electrocuted. In a TT system, you actually don't use the neutral as your ground, you use the ground rod as your ground reference. This has benefits and drawbacks, but the main drawbacks is that the impedance of the earth is now considerably higher than a couple of ohms, it goes from maybe 16 ohms to being a few hundred ohms, but it is much, much safer. This is why the term going to the ground is used, because it can literally go through the ground to your transformer station.

[@TheGothicSecret]

Man. Thank you. You explain it just excellent. Specifically with image with the samr outlet for two devices

[@YourNotSupposedToSee]

Midas M32 is a clean and easy board, I love ‘em!

[@Carbalifo]

Fantastic explanation :)

[@giovannigalvez8598]

I like your story about the power supply issue. Now at live gigs there are so many power supplies from phones, laptops, pedals, etc. There are random noise and buzzing sometimes and it's because of this. Not to mention everyone at concerts have their phones out. So we switched to Star Quad XLR cables and that did the trick.

[@GregoryGuay]

I have a modest home studio, but I’ve been reading about star grounding, was hoping you would mention something here, but do you have any other explanations of this for those of us that have the luxury of wiring scratch? Simply do a run or every audio dedicated outlet?

[@JAROCHELOcesarcastro]

Thank you!! I want to learn more about the ISOLATION TRANSFORMER

[@freddiecauseyii9419]

Thanks for the video.

[@benplachy8564]

Very helpful, thank you sir!

[@TurboLoveTrain]

Anyone who does audio needs to watch this.

[@MathCuriousity]

Just curious - if I get shocked touching two appliances at once but not either alone, is that me creating a ground loop? How does that work?! Thanks!

[@PepekBezlepek]

fantastic explanation! I understood exactly what I was missing ♥

[@DFar-oj1yc]

Thank you

[@branislavcrljenica2584]

6:41 *???* *Let's* *talk* *about* *phase* *........* *????????????????????*

[@konradschaubert5520]

6:28 looooooool

[@Zerogravityremix]

Hello thank you so much for sharing this information

[@JineaneCastro]

thank you!

[@elephantgrass631]

Great video, but I feel it's incomplete. Yes ground loops happen, and can be solved as per your video. But what's REALLY happening? What specifically a hum? Why not a buzz? Or sometimes both? What's causing a sawtooth like wave to form and not a sine wave? Did it start as a sine wave then get cancelled and sort of turned into a triangle/saw? That's what I'd like to know. Thanks for the video. I feel it's half way there to the complete answer. I'll check out your course.

[@PhillipJohnsonphiljo]

I have been trying the lift option on both my breakout usb sound card and my DI box, neither of which do anything to remove the ground hum. Does anyone know why the ground lift option wouldn't work? Is it because I might have multiple ground loop paths through my audio devices? I'm going to try the same power socket for the desktop and laptop in question tonight and see how that goes. My signal cables are decent quality and I am almost sure it's the 2 earth pinned computers that make the ground loop. Here's hoping...

[@RichardDuenaz]

whats the differance between breaking the ground pin off .and a ground lift switch .im assuming either way .no matter which product used its all the same it disconnects the ground is this correct .if so then either ay still have the same level of risk of death by electrical shock

[@alfred-pc9sb]

Ground lift switch is something different. Do not break the third pin off.

[@rahulsawant1493]

Sir , there is noise from speaker when any electrical switch is on or off , can you suggest solution for it ?

[@StagnantMizu]

wtf then there is currently leaking from your amp aka faulty equipment might be dangerous

[@BobGnarley.]

I am plagued by this ground loop that ruins my guitar playing lol. Have tried literally everything I can think of at this point and put a lot of time into solving it.. starts to feel hopeless. Especially with everything in the same socket.. could it be the power strip? could it be the fact the interface is powered by USB? who knows at this point all I know is most other people with a focusrite have no issues lol

[@RichardDuenaz]

whats the differance between breaking the ground pin off .and a ground lift switch .im assuming either way .nomatter which product used its all the same it disconnects the ground is this correct

[@patricklouie7737]

The difference, theoretically, would be safety, because you now have a source to the Earth that is the same conductor size as the requirements for the system. You would have a safer Earth. What this guy doesn't seem to realize, though, is that the ground is typically shorter to the lying ground, which means that the other device will automatically also be grounded to the main ground of the AC line. However, it's not as safe, because you're now using musical wire as your reference to the Earth, rather than using actual conductor that is thick enough to be able to handle the current long enough for the brake to trip in order to prevent any kind of fires. So while, in theory, isolating the ground pin of a socket outlet is possible, and it should give the same result, you risk setting your cables on fire instead. Just buy a ground lift. It's much cheaper, and it's much safer.

[@StagnantMizu]

I got the humming noise, my DAC and amp are on the same powerstrip but none of them have a ground pin. should I connect the chassis of my DAC to the signal ground on my amp? or wtf is happening

[@patricklouie7737]

If none of them are connected to a ground, you could test the following. If you're using, for example, a guitar with an exposed guitar jack pin, try and place your hand on the input jack's ground to see if the noise goes away. If it doesn't, try taking off your shoes and socks and stand on the floor barefoot, which makes you much more conductive, and thus you can dissipate the charges much better. If it stops, it's likely due to the lack of an earth. If you connect your system to an earth, or the physical ground, the humming should go away because now there is somewhere for the charges to go. If you have just isolated power supplies, then there's no potential difference between the ground and whatever sources you're picking up, meaning that the charges that your shielding picks up have nowhere to go. Also, it's not recommended to do the test with the guitar's output jack if you're on an elevation higher than the first floor due to the fact that you get quite isolated from the ground, and it most likely won't work. In that case, what you should do is to take a ground reference from one of your sockets and place it onto a grounded reference to see if the hum goes away. It should.

[@maheshkumarctla]

Guitar connected to mixer also makes noise eventhough guitar not connected to a plug point. Why this happen

[@pmk3574]

Thanks. Problem solved!

[@Noone-of-your-Business]

That still does not explain what ground difference actually _is._ How does it generate an audible signal? Also, how does the signal from a DI box with "ground lift" get to _flow_ between the DI box and the mixer??

[@HomidWay]

Maybe that answer is too late, but at least it is an answer. So, sound is basically just AC voltage, and technically in your outlet there is already 60/50hz "sound" and 60/50hz is how many times phase in your live wire changes from negative phase to positive(technically not like that but that just easy way to explain). Voltage is difference between potentials, if your Ground or Neutral wire is 0 volts and your live wire is 220, then your voltage is 220, but if your neutral wire isn't actually neutral and has like 10 volts on it, then voltage is 210 at that point. The thing is voltage on neutral can differ slightly between outlets because no connection, and no wire is perfect, and this difference creates two problems. First, now your ground has current running through it, it's most likely extremely small, but may be picked up by sensitive devices, like mic and line amplifiers. And second problem is that your ground is not 0 anymore, and ground is the base for your signal, imagine your sound at it's loudest make AC at 10 volts, if you'll have even 1 volt ac on your ground, then even then signal is 10 volts at any frequency(or multiple frequencies) your base is moving 1 volt up and down 50/60hz so basically 10% of your sound volume will be this 60 hz hum(reversed in phase to line btw, but this is not important.. Is like you measure height and your ruler change it's length all the time, you measured that at this point there was 10 at the ruler, but next time you check it's 9 in the same place.

[@HomidWay]

And for Di box, ground is just a wire which conduct electricity to place which can accept current, usually, you quested it, literal ground, in sound ground is reference, just something to compare signal to. it doesn't matter there this reference comes from, if it's constant across devices then it's fine.

[@scott7521]

This dude's funny

[@scribblecloud]

i live in europe and we dont have the ground pin and i have both devices connected to the same outlet but i still have buzzing?

[@ilmarss]

In EU we have those metal things at the sides of the socket, not the 3rd PIN.

[@XewHweX]

To live in Europe and not know electric circuits are grounded?

[@earthsteward9]

I haven't tried it yet but I don't think toasters would taste very good

[@narrator-timothymckean]

Ironically, that's nearly how they made that sound for the lightsabers.

[@StagnantMizu]

cool fact

[@ccnp2009]

Issue resolved by using a ground lifter.

[@bingdong8571]

75000 dollar ht system broken. 9 dollar used ground loop isolater from amazon= FIXED

[@hintoninstruments2369]

Yet another incorrect explanation. The 50 or 60Hz hum doesn't come from "Earths at different potentials" it comes from magnetic fields in the area of the loop which are then introduced to the signal circuits by common impedance coupling and amplified. If mains outlet Earths were at different potentials it would mean that a current is flowing between them and that would cause an RCD to trip. Yes, there is a slight difference caused by a single coil pickup, but it is microvolts like the output of a ribbon mic. The real problem is mixing unbalanced and balanced equipment and not conforming to AES48 recommended practise. Many products confuse the difference between a signal common and a chassis screen, both should be connected to mains Earth, but not randomly. The screens of balanced cables should only be connected to chassis and not the signal commons. You connect to the planet for safety and discharging induced charges, but it should not be part of the signal circuit except as a potential reference. (Non static) Electricity flows in circuits, it does not flow to the planet like water. Note that I have not used the word "ground" to explain this, once you do that people can't see the distinction.

[@johnxthan.mp4]

now explain this to me like I'm 5 years old

[@louisvanharten2934]

An antenna is just a loop of wire. The electric wires powering all the appliances in your house act like the world's most boring AM radio station, and if your ground is a big loop, you've accidentally built a radio receiver, receiving that same boring signal. Hence, hum. By being mindful of your ground connections, you can reduce the effectiveness of your "receiving antenna".

[@lwpweb]

same ground is not solving the problem

[@omniyambot9876]

Using isolation transformer makes grounding useless anyways. so remove the grounding pin.

[@RideAcrossTheRiver]

Never cut off a ground pin.

[@michaelmaloney3480]

Just plain wrong

[@sdriza]

that's one way to put it... could also say, "erroneous" or maybe, "not completely correct" to soften the blow a bit, no?

[@MyAngelHasDied]

How is it wrong, can you explain please? I'm getting a headache

[@revilerred7440]

The delineation of electrical ground being a diversionary safety path for electricity in case of a fault as opposed to the signal low end-sounding ground was itself alone worthy of a sub. No one has ever put it that simply and accurately.