What's the difference between the passive and the active di box? What's the difference between mic level and line level? Thanks and YESHUA GOD ALMIGHTY bless you!
A passive di box is using a audio transformer. A active di box is using a op-amp, aka active electronics. A passive di box is better to use, for it gives you minimal trouble, but it's audio transformer have to be of very good quality.
Audio cables and power cables should be loomed away from one another and if you still have a hum...you nd to replace a audio cable somewhere and finding it is easy by disconnecting one at a time.
I worked in the ROV industry. We sent control signals and video over umbilicals 1000 Meters or more in length. Ground loops and noise were serious issues as well as the risk of fatal electrical shocks. First we had our power supplied by an Ungrounded Delta Wired Generator. This eliminates a power return to ground making operations much safer for personnel and equipment and while this option really does not apply with sound equipment I supplied it to show sometimes the problems can be caused by normal safe practices. We eliminated or mostly got rid of our ground loop problems by isolating chassis or electrical ground from any signal ground or signal path or return. In some systems we could have as many as four different isolated grounds. The bad news is that signal voltages could float above normal electrical ground but there was no path for current to flow. I would like to see the professional audio and sound operators and manufacturers adopt this philosophy by using totally isolated signal paths eliminating ground loops by doing so.
I was having this problem a few months ago with our PS3 when I connected it to one of our stereos. Tried using grounded adapters for the outlet plug like someone on a forum had recommended, but that didn't work. Figured out that the AV cable was sitting on top of the power cable from the unit. I simply cut a small 3" length of pipe insulation (which I already had) and placed the AV cable inside of it, then let it rest atop the power cable, instead. Hum immediately went away and hasn't been back. Wish I had thought to do that, first; would've saved me a few bucks on something I don't use. :)
@@randinonsense7360 pipe insulation, it's a foam rubber sleeve like a pool noodle. I think it worked for him because it physically separated the two cables enough that the AV cable didn't pick up any EM radiation from the power cable.
Cutting signal wire ground could introduce RF noise due to antenna effects. However, these effects are (almost) non-existent in audio systems due to the cable and wavelength. Unless the system is >6km (λ/f) Cutting the signal ground but leaving the shield intact is the safest budget solution.
A good video. In sound systems, howling, hum noise, ground noise, and oscillation (higher frequency instability) are big problems and each one has its own ways of being eliminated or attenuated. Oscillations sometimes have to do with amplifiers with very high feedback loops or with output and input lines to close to each other. Ground noise has to do with the so called ground loops while hum noise has to do with micro lines peaking up harmonics of line frequency that propagated by air or by AC lines to close to audio lines. Howling has to do with microphone and loudspeaker closed to each other or resonances in the space where the system is used. To attenuate this trouble we have to reduce sound level, reposition micro and speakers, use frequency shifters and/or equalisers. The PCB ground line is normally connected to the chassis somewhere and it is the main source of ground hum.This hum can be attenuated if we cut this direct connection (it is a short circuit) and connect both grounds through a wire wound resistor of about 10 Kohms having in parallel wit it a 2 MF ceramic, polyester, etc, capacitor.
I used to work on sound systems for churches and my own church drove me insane with hum. Had to do many crazy things to get it down and quiet. What do you have going on???
Roger Stevens It's a brand new Ibanez bass and a brand new Mark Bass amp. I bring it to my house and plug it up; no hum. I take it to where I play it, plug it up; constant hum. I've tried ground lift adapters, Plugging in different outlets, everything.
I have the Shure Wireless MIcs using XLR cable to connected BMB karaoke mixer input. It works fine, but want to add the compressor of BEHRINGER MULTICOM PRO-XL MDX4600. After connect them all together. IT have the hum sounds. So I think I need the DI box? if so, do I need just 1 DI box or 2 boxes since I currently have 2 mics? Thx
Very knowledgeable description of my buzz/hum. The solution might be beyond my budget. Thank you for sharing your expertise. Based upon your explanation I tested a couple things. Unplugged all devices, mouse, external hard drive from the usb ports and unplugged AC too. When I move the AC cable close to its import connector or my computer the buzz grows. I'll have to record without it being plugged in. Thanks again for your help.
So, my chain looks like this: guitar->usb audio interface -> pc(running guitar rig/bias/etc). In this case there is a lot of hum,but some noisegates can handle with it, but when i add a preamp beetween guitar and audio interface no gate can help. Now,the question is - if it's the groundloop conflict and if a dibox may help solving this issue? Many thanks anyways
Great explanation of ground loops. Just being picky here but when you say '180 degrees out of phase' you are actually talking about opposite polarity. Phase implies a time delay, having the same signal just delayed half a cycle. Your statements get the point across but to be accurate you should use polarity.
Yes, opposite polarity. In-phase would imply exactly 180 (degrees) of phase, anything other than 180 (degrees) are referred to as "out of phase." Phase does not imply a time delay. If you calculate it 2 phases (1 cycle) at 60hz (60 cycles or 120 Alternating polarities a second. But your ear wouldn't hear this as a delay. Phase refers to a relationship between positive and negative polarity in the sine signal. As it pertains to microphones and pick-ups, out of phase would imply an auditory delay not a delay from a ground loop.
Indeed Douglas Sebens, it is a common misconception. It is not 180 degrees out of phase, it is inverted. However, the ground loop explanation is fundamentally wrong in this video, so not so great.. There is no potential difference between the earthing connections of wall outlets if no devices are connected to them. Once a ground loop is created (or any loop of electrically conducting material), a current starts to flow through the loop, creating the potential difference. And by the way, jon wilson, you're talking shit.. it makes no sense at all.
If a laptop has a ground loop, just unplug it from the wall and use battery. Also, there are other such transformers to break ground loops from Whirlwind, Radial, etc.
I just moved to a new house and I'm getting one hell of an annoying high whistle that comes and goes randomly while this has never happened before in my old house .. I'm using my exact same setup that I've been using for ages .. equipment are not faulty .. I've tried each and everything that might come to mind.. switched off every other device in the house to ensure no interference or anything and still.. same issue .. tried a different sound interface .. same issue .. different guitars .. amps.. pcs..the only way I can get rid of this shitty whistle is by making sure that none of the audio setup is plugged into the wall and just use an external power source.. my laptop's battery for example which means that it is 100% an electricity issue ... Got a technician and he didn't know shit and when he gave up he advised that it's an issue with my equipment which is bullshit ... I'm desperate especially cuz this stupid whistle makes its way through to my recordings which means I can't even work anymore ..(I record for bands and for my own music ofc) Any help
I had a hum in my system; however, when I plugged in an external monitor to my laptop the hum disappeared. So until I was able to buy a new laptop I hid the external monitor under the table. Boggled my mind.
DJKJSeph I was just wondering if a potentiometer (I’m no electronic engineer) or something could be attached to the ground somewhere to adjust the voltage hoogily boogily 🤔 Don’t worry, I don’t even know what I’m talkin about 🤪🤘🏽
I solved my hum. I used two channels of my Mixer/Amp, plugged the left and right RCA cords from my laptop into separate RCA to 1/4 inch phono jacks, one in each channel.
Using a Surge protector power strip, I only use ONE wall outlet to power everything: mixing board, powered subs/monitors, processors, etc. = ZERO HUM !
Old vid but can anybody help so i have two amps+crossover+mixer i connect then via Aux cable to my Pc and suddenly today a high pitched hum or signal noise appeared and ONLY when gaming so does anybody know what is the issue these amps etc. Are all conmected on two extension points BUT from the same wall socket so im unsure whats causing this all the cables are fine so unsure whatsupp
I have a question, and I have no knowledge on AV, so I’ll try to explain my question the best I can, but at my church We upload the sermons live to Facebook, the audio for the video is what is coming from the board(not a separate mic) and there is a hum in the video audio, so how do I know if I need a 2 channel line level decoupled or a DI box?
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So i plugged the (unbalanced 1/8") Line-Out out of my computer into the DI-Box IN. And i plugged balanced 1/8" to XLR from the DI-Out to my active monitors. I still have ground loop buzz when the harddrive works or i scroll the mouse. What can i try next?
My home theatre hums as soon as I turn it on regardless of if it's connected to anything else. I'm even using optical cable, so this should not effect it anyway. Do I just have a crappy speaker?
I have a balanced xlr that goes from a preamp pedal and into my computers soundcard which has a 3.5mm input. My question is....are line ins on soundcard balanced....unbalanced....or capable of handling either? Reason I ask is I have ridiculous noise and I'm trying to narrow down exactly where the issue is....without buying yet more things that ultimately have no or little improvement. I'm thinking a 3.5mm in line ground loop isolator might be the key....but I'm not certain.
What a great video. My set up is as follows - Macbook, connected to a wall powered mixing desk via a USB insert - in that mixing desk I have an XLR condenser mic connected, using another wall powered compression unit, connected through an insert on the same channel as the mic. No problems, no ground loop. The problem began when I tried to do something very simple, which was add a 3.5mm TRS to Dual 1/4" TS cable between the mixer and my DSLR camera,, so that the mic runs through the camera (for better lip sync on live stream/conferencing). Instant ground loop and very loud hum and buzz and I couldn't work out why. Now I know why. I'm using my DSLR camera as a webcam, which is also wall powered with a dummy continous battery - when connected to the mixer, this means I have two different wall powered devices running through it (the compressor and camera) which is obviously causing the loop (with the USB connected wall powered Macbook which may or may not be adding fuel to the fire). I've ordered one of those decoupling boxes and will expect that this will work, when connected between the camera and mixing desk. Fingers crossed.
All In the same damn room for me.. I’ll be playing my ekit which I can finally do at night now turned down and something will come unplugged and the loudest HUUUUUUMMMMMMMMMM shakes the walls. Really starting to get annoying now…
Great video! I'm a street performer and I face humming when I plug my amp (battery powered) and my pedals (which run through a power bank), if I swap my eletric system for a car battery powering everything, would the humming quit?
Yes. But you would need to make sure about power consumption of both of those systems, as a sudden peak in each one would hinder the working of another one.
I've a turntable and an hi-fi both without earthing to wall. Other source devices are connected to the same wall power strip, noone with earthing. The grounding between these devices is linked through the unbalanced L+R phono cable with the earth thiny wire. Noise is present and follow the volume level. But still present if the turntable is disconnected from cable. With same speaker I've also tried two different hi-fi system. I can't figure out how the problem can be generated by AC and how any DI Box can be help in this scenario..?
I have mains hum probably due to a ground loop between hi end hifi components connected to the same outlet. None of them have balanced inputs or outputs. If I used the unit you recommend surely it means I have to use more interconnects and wouldn’t it interfere with the purity of the sound in such a system? My DAC and transport are from China. Is there a chance this affects the situation in any way, by having slightly different voltages?
there is one instance with laptops that will sound like a ground loop but it's not and that's noisy battery charge circuits or power supplies a.k.a. five dollar replacements off eBay or Amazon with no filtration and certifications. And if it is a genuine power adapter it's usually poorly designed charging circuit and hopefully you can get through the presentation on battery.
What if I only have one device in the socket with no other devies interfering with it, but still get a ground loop buzz? The buzz also only happens with one guitar amp and not with others.
I get a lot of humming while using my phone through the mixer ,, what device ,, which way is the best way around .. which isolator is the best one to use .. (inexpensive
Buy yourself a Furman conditioner that should clean up the noise. My brother put led lights in my room and cause all kinds of noise. I bought and installed the conditioner no more noise.
Very informative video - but I am buffeled... I am using this connection: Instrument -> Mixer -> [via USB] -> PC and the sound out from the PC speakers. When I am going into my DAW (Cubase 8 LE) and bring up the amp/fx plugins to start recording it screams like HELL :-O I've tried several sollutions, but I can't get rid of the hum/squealing sound. -Are there a option to get a ground loop filter on the USB cable wich goes from the mixer to the PC? - Hope that someone have a sollution for me. -tnx! -Arnt Petter in Norway
Hi, great video great explanation, subbed. I'm having a problem with my rig and beg for your help to understand what's the cause. I plug my guitar (Ibanez RG with two Humbuckers and one single coil, properly grounded and shielded) straight to my Line 6 POD HD500x (wich is powered by a two pins plug transformer (I'm in Europe, so, no ground connection) and then monitor it through headphones. I'm getting a 50 cycle hum that goes away when I touch metal parts of guitar or POD. What's the cause of the hum? Lack of ground connection to the wall socket?
although it is most likely your line 6, check if you're plugging the headphones to the designated output. If you're plugging it to the line out, or the main out that goes to your amp, that might be the issue. also, the line 6 has a ground connection, which you can plug some wire into or touch with a screwdriver. If none of this works, get a grounded plug. Because we have grounded plugs in Europe too.
I am getting AC Hum and Im not sure if this video helped. My setup * Laptop plugged into same AC powerstrip as Monitors * M-audio box (plugged into laptop via USB) * then 2 KRK monitors (RCA to 1/4" connector coming from M-Audio * Then my Mic is plugged into the M-audio box with the 48v turned on. I get a hum unless i touch the metal part of the XLR cables. As soon as I let go it comes back. Which device from this video could help me and where do I place it? Please help!
i dont know what the hell is going on in my setup but i know every time i move it i need 7 days to get rid of all the problems, i actually must place an interconnect cable between monitor and ground breaker or sound card in such a way that it must be on my keyboard, it really wants to fuck with me. I tried to pay attention to cable management after a day of moving the cables its back to a total cable mess but there is no hum. I dont know what makes the ground loop, cuz ive moved it so many times i dont even know what goes where, but its a big pain in the ass for a guitar or mixers with powered monitors
So, I currently have an odd setup, so perhaps you can let me know a better way to deal with it. I have 2 different dacs feeding two different audio sources, when either is used individually, the ground noise is essentially zero, but when the two sources are merged, there is a horrible buzz. The signal is sent stereo via 3 wire, and I assume the problem is the shared 0v ground aren't the same on the two sources. One of the dacs is grounded to earth, but the other takes DC in and isn't ground referenced at all, i assume it functions on virtual ground. How would I mix together these two sources without the grounds clashing then causing hum? Basically, I am attempting to have two different audio sources play on the same set of speakers, without buzzing occurring when more than one source is hooked up at the same time. Currently my solution is use a 2 way toggle switch that I have to flip manually to switch between the sources grounds, but I hate this solution.
excellent video!! I live on 4th floor in a 120 year old block of flats in Madrid. The 240 juice fluctuates on a daily basis . i dont think the earth cables get all the way to the bottom!! Thiis presentation was very informative . THANKS
Excellent presentation + clearest explanations. --- I have never found an explanation for similar problems in a 2 wire (AC) 220V European circuits, though. Are those boxes identical in construction and use? Is AC filtering done the same way, since they don't have 3d prong for ground? I thing that Alectro is the place to get answers and... to shop. Bravo!
Just bought a new amp and power supply. Both devices were tested at the retail store and worked ok. However, having connected the amp and psu to ac power at home when i plug input cable or even touch one of the input terminals with my bare hands i get a deafening hum from the subwoofer. Also a problem i had ignored before even purchasing the amp and psu when i touch the bare audio input cable from a receiver I get shocked just a tiny bit. It seems like my AC is not earthed properly or something, I dont understand much about electrical engineering. How do i fix my problem?
hey i have all my audio stuff plugged intto the same power bar but as soon and i turn the amp that powers the sub on i get a hum. even with nothing plugged into the amp other then the sub it still hums. and its only a 2 prong plug for the power to the amp. any ideas thanks.
***** no i think that`s wrong i`ve got hum and it sometimes will happen with no sound - just volume i had the amp checked when i bought it 2nd hand so i know for a fact it`s fine - the guy is a classic repair man - so i know it`s an earth thing as far as i know it could also be wiring getting crossed behind the amp or mixer or amp - when the wires are close together and all criss-crossed - this can cause a hum as for the earth - i think this is the best way to fix hum - but i`m unsure how to achieve it - unfortunately
Nope. If you want no hum from your amp, take out the transformer from it, build a box for it, and put it at least meter away from the amp. Also, if you use two amps, make sure their input is only one long cable going to it, and then splits into two amps as close as possible, with good quality splitter. Not two long cables. Make sure you use one outlet, like, use one outlet splitter for all the amps, and the signal source included, like your computer or even charging cellphone. Got it? Every thing is important. Now go and fix that annoying hum.
I get crackle sounds from just 1 speaker in my home theater since I added a 7ch amp. I can't seam to solve the issue. What should I do? Some told me to buy a conditioner. The amp and receiver are connected with unbalanced rca as the receiver doesn't have balanced xlr's. I also have the amp connected in a different outlet because when the amp was on the same outlet it was shutting off du to possible line sag.
According to professional audio manufacturers like Apogee, your comment "all sound systems need to be balanced" is only true for live sound systems (club, festival, concert etc) where the mixer is at a far distance from the speakers/monitors. For home recording studio purposes this is most likely untrue. Its the long cables that require the system to be balanced. In most home studios the monitors are going to be nearby the audio interface therefore not requiring a balanced system. I've had no related issues using an unbalanced interface configuration.
The main problem with connecting many devices to an amplifier is the inadvertent formation of so called earth loops, as an example your amplifier is earthed at its mains power socket, then gets earthed at the source of signal which could be a tape recorder, which is also earthed to its own power socket, then you connect the output of the tape unit to your amplifier, you also have an earth in the connecting leads, this causes a loop, and any loop will pick up electromagnetic signals, so you need to break the loop, which means you earth all devices to one single earthing point, and there is another thing about output connections, so from a power amplifier throwing out 1000watts of music power, it will be sending very heavy currents, and if the heavy current path to an earthing point is also being shared by signal earthing, then you are likely to get noise and instability due to voltage drop across copper tracks which also share this track with signal earth return currents, in many ways current flowing through a wire will meet resistance, so at the starting point the voltage drop will be minimum, as the length of wire increases, then by the time the current leaves the wire, it would have dropped some of its value, and so it would reach its load or destination a few millivolts lower than when it started, normally this may not present any major problems, but can do so in a badly designed amplifier earth plane, adding resistors can suppress some of this unwanted noise, but it ca also reduce the sensitivity of an amplifier, which can give you less amplification and or lower peak power, spo a trade off needs to be made, some amplifiers have build in resistors at their input as well as RF suppression, from modulating radio station signals, where by you may hear many radio stations as a very weak background radio going on. this can be suppressed using inductors and capacitors, so those who don't understand loops and voltage drops, can do experiments to get rid of unnecessary noise without compromising amplifier response, remember adding caps across inputs can suppress radio signals but can also effect amplifiers high frequency response, series inductors can reduce RF signals whilst not effecting high frequency response. You can do many things for yourself, learn hard way as I did. and its all the fun, and you feel good when you have achieved good results. remember some amplifiers can chuck out so much high frequency that you do not hear but can damage your HF tweeters.
Great video! Do voltage regulators help? My system also has a hum but only Ribbon Microphones bring it out clearly. As you described in the video, my 50ft. snake amplifies the hum signal very well. So I wonder if I plug all my equipment into a single Voltage regulator such as the APC LE1200, would that get rid of the hum?
+OZ B Just realized that I may need a Power Conditioner - not a regulator! Going to try the Furman M-8X2. Anyone else try that unit to eliminate hum and hiss?
can anyone help..my Bluetooth speaker start to make this noise when connected and music play..when pause or stop the noise stop..just saw it now that I have only 2 pins...not 3..i have 2 stand speakers..both connected by cable..with the main speaker plug in socket by a 2 pins head plug...can anyone help please
This sounds familiar. We had a problem for a while in our rehearsal space where I would get shocked if I touched my guitar strings and the cage of an SM58 at the same time. I assumed it was a ground loop between the mixer and my amp, so I just started mixing and matching outlets throughout the room, and found that as long as my amp was on the same power strip as the mixer, I could plug my pedal board (about 6 analog pedals daisy chained on a 9 volt power supply) into an outlet on a different breaker and avoid getting shocked. So I'm not sure exactly where the loop was, but I broke it somehow!
At 14:05, if the laptop's input is stereo (unbalanced) and I'll send signal to it from an unbalanced aux-send, how would you make the connection balanced? Thanks!
one thing you didn't cover is the Hum between a usb devices from a (audio interface) connected to a computer mixer and synth equipment. another thing is USB midi between devices often introduces more noise.
Actually, this video helped me tangentially. It prompted me to look at the many connections in my modest shack and reconnect some of the AC feeds. This provided a modest improvement, so it seems that I am on the right track. It's still humming, since I couldn't pull the rascal out of the multi-tap feed. It's funny though, the problem of humming just suddenly appeared. It's freezing here ... nothing works ... time to call Ghostbusters.
I've gone through the content along with conceivable way of explanation on subject & pattern of elaboration of issues & there causes & solutions. Big thanks for the same!!! It would more useful , if available in Hindi (Hinglish) language retaining of technical terms in English!!
Having circulating earth's for signal cables is against Australian standards, so it isn't frowned upon. If the system is high voltage then an earth grid is needed to limit step potential in the instance of a fault.
Is this normal to happen if you plug studio monitors directly into the wall? Would this be an issue within wiring within my house and could a power conditioner help here?
Ground links should always be considered because of their uniqueness to the spere magnetism system...The audio line and ohm link is imperitive to understand.
A laptop PC will almost certainly have a double insulated external power supply, so it will not have any earth connection. A desktop PC will probably be grounded
This video just helped me with a year long problem in my guitar setup. I had been chasing the problem, not getting results, and about ready to move out of my house because that had to be the problem thinking i had tried everything else. Thank you so very very very much. I added a studio monitor to my sound about a year ago and plugged it into an outlet on the other side of the room. Today I changed it to match where my amp is powered. Thank you so very much.
thank you very much for this video. i'm wondering if the DI box capabilities of audio interfaces can suffice or should a separate DI box be used because i still get nasty hum out of my electric guitar when i connect it to my audio interface to my laptop.
If you use a DI-box with a audio-transformer, it will make an unbalanced audio signal to a balanced audio signal. To get good audio quality you need to use high quality audio transformers, from Jensen Audio Transformers, Lars Lundahl Audio Transformers and others.
love your explanation, clear, crisp and correct.. as an electrical engineer, I appreciate the way you explain the balance signal with differentiate amp to eliminate noise while producing 2X the signal.. I'm hoping your next video is going to be about eliminating feedback with home entertaining system .. singing karaoke at home produced a lot of feedback, and I bought a few feedback destroyer devices, but none of them seem to help.. Thks..
