A humming monitor? Why is it not connected to the volume?

johanmattsson

New member
I have a new monitor (loud speaker) and I noticed that when I plug my external screen via HDMI to my laptop, my speaker starts to hum. Is there a way to avoid that, i.e. is there another screen I can buy that does not give me this noise or is there perhaps some device that could get rid of the unwanted sound?

A thing that puzzles me is that the amount of noise is constant. When I change the output volume on the soundcard will the noise still be at the same level and turning the volume up on the speaker will also not change the volume of the unwanted sound.

I am absolutely not sure if this is a common problem with HDMI connected screens and I would very much like to know if there is a good chance I can fix this with a new screen or if this likely will happen even with another screen.

Setup:
Screen (Philips 243V7QJABF) -> Computer (Surface Pro)
Computer (Surface Pro) -> USB audio interface (Edirol UA-25) -> Monitor (Yamaha HS8,) balanced input and output.

IMG_0285.jpg
 
I don't know much about HDMI issues.

However . . . you can try a few things

1 Move the monitor and screen away from each other. Is the noise contant or does it change?

2 In any case, shift the interface from on top and away from the monitor (and also the screen). Does that change anything?

3 You are using balanced cable from interface to speaker? (Is it just one speaker, or do you have a pair?)
 
It sounds to me like you have a ground issue. Unplug the laptop power and see it the hum goes away.
 
AFAICT that Philips monitor uses a 3 pin, i.e. earthed mains input. You therefore have my friend a good old fashioned earth, aka ground, aka hum loop. Screen is earthed, monitors are earthed, Surface Pro 'might' keep earth through PSU (they SHOULD know better these days if so). Then you have an earth in the AI USB, and the HDMI cables AND the balanced feeds to the speakers. Some how you must break at least one of those SIGNAL earth paths...N very B! YOU MUST NEVER EVER REMOVE ANY MAINS SAFETY EARTH CONNECTIONS!!

Try the Surface on battery power, i.e. diss the power plug. If that removes the hum you could look for a 'Class ll' double insulated laptop PSU. One such is made by Duracell and is a universal unit, about $40 mind.

Another solution is a transformer isolator between AI an speakers. The Art Cleanboxll is well respected.
A zero cost solution is to cut the screen connection (pin one) in both XLR connectors feeding the monitors but if you do that be sure to tie on a label to show a non standard lead.

You could OF COURSE look for an alternative to the Philips that does not have an earth but it does look a very nice monitor!

Dave.
 
Thank you everyone for your answers. It makes me very glad to see that there are nice people that are willing to share knowledge.

Moving the monitor sound card and laptop did not have any impact on the sound.

I have ordered two speakers but I have just one at the moment, the cable is balanced and the connection is also balanced.

Unplugging the power to the laptop did not change anything and I tested this with another laptop as well, same noise. Turning off the screen did also not help, the only thing that did work was to unplug the HDMI cable.

I have googled around for a monitor without ground but it looks like a feature that screen manufacturers don't advertise very well.

Does anyone here know of a screen that might solve the problem? (How confident are you that it will work from a scale of 1 to 10?)

Cheers
 
c14 panel mount iec plug - Google Search

Ooo! That's put me on the spot! You can never be sure about a remote diagnosis, especially about a slippery bastd problem like a ground loop so I'd have to say 70%. But, let us first be dead bang sure..Does the mains input on the Philips monitor look as in the link? Detail form might be different but it is the THREE pins that matter.

Strange diversion perhaps but do you own a domestic flat screen TV? If so it will have at least one HDMI port and, I must have had at least six such TVs (have 5 in the house atmo!) and seen many more and do you know, I have never seen one with a 3 core mains lead or IEC connector!

So, if you have such a telly try it as the system monitor. I will admit that 3 pins are common on computer monitors although I have had quite a few that use a chunky 12 volt 'line lump' and they are often 2 pin mains in.

This whole problem of ground loops is a bugger and can be tricky to resolve. Often the last resort devices in the chain is/has been the active speakers but many now are being designed with two pin mains connectors and so are earth free. In fact we are now starting to see hum problems because of LACK of an earth anywhere!

Dave.
 
Last edited:
Does the hum go away if you turn the monitor off?

Does the hum go away if you leave the monitor on, but unplug the hdmi cable?
 
Hi and thank you again.

The hum is still there when I turn the power to the screen off but I guess that the screen just goes into some kind of power saving mode instead of turning off.

The hum disappears if I unplug the power cable from the screen and the hum also disappears if I disconnect the HDMI cable, even if the screen still is on.

The screen has a three pin connector so i guess one of them is ground (as you kindly explained). The monitor (loudspeaker) also has a three pin power connector but it looks like the noise problem on the ground does not have an impact on the monitor, just the screen.

I only have one screen at the moment but I will buy a new screen if that is a plausible solution to the hum problem.

I also tried to swap the power cable but it looks like the noise problem still appears.

The Art Cleanboxll looks like i nice gadget but I would prefer if there was a way to stop the noise already in the HDMI input, in order to make sure that noise does not get into the inputs. I might be wrong but I guess that if this kind of noise gets into the sound card output, it will also make it into the preamps on the sound card some way.
 
It sounds very much like an earth loop. When either screen or hdmi is unplugged, the loop is broken and therefore no hum.

The other thing you can try is to make sure screen and speaker get theiri power from the same outlet via a powerboard or similar. Once source of earth loops is a difference in the 'earth' between different power outlets in different places.
 
This might sound daft, but can we make sure the hum is what we are all imagining - a continuous 50 or 60Hz hum. Not a buzz, or harmonically rich data type noise? Curing these is very different. HDMI noise is nowhere near as common and usually is a weird sort of sound. A traditional low frequency hum can be cured by breaking the loop somewhere. Maybe the HDMI cable is wired with the screens providing the loop path. Systematic swapping and subsitution of cables is part of solving real ground loops, but very difficult to do without a junk box of surplus cables and power adaptors.
 
This might sound daft, but can we make sure the hum is what we are all imagining - a continuous 50 or 60Hz hum. Not a buzz, or harmonically rich data type noise? Curing these is very different. HDMI noise is nowhere near as common and usually is a weird sort of sound. A traditional low frequency hum can be cured by breaking the loop somewhere. Maybe the HDMI cable is wired with the screens providing the loop path. Systematic swapping and subsitution of cables is part of solving real ground loops, but very difficult to do without a junk box of surplus cables and power adaptors.

Hi Rob, I think an HDMI cable is going to be analogous (!) to a USB cable? What I mean is, both have a continuous screen but both a negative DC return which connects ultimately to chassis in the equipment.

I once painstakingly cut a 6mm band out of the screen* of a USB cable to try to fix a ground loop, did not do bugerall!

OP did not tell me if he had an FSTV in his house? Would be very strange if not? But, if indeed not then he could pickup a 22" telly from a charity shop for $20 or so, I see them in the Scope shop all the time. Often cheap because the RC has been lost. Do not need it for OP's test and they are all available on't web should he want one.

OF COURSE! If he looks for one be DBSure it has a 2 core mains lead and HDMI but I doubt he will find anything lacking either.

*I had thought of a gadget. A 5V DC-DC converter, a cap to break the screen but keep an RF bond and the data wires can just go through? OH!! To have the eyes and energy of a 60 yr old!

Dave.
 
Hi. I got the seccond monotor today and it is completely silent, no noise. I tried to swap the cables but it did not change anything. Should I return the first one and ask for a new one or does the fact that my screen seems to be involved indicate that the problem isn't due to a problem with the speaker?
 
If you plug one speaker in and it's noisy, then unplug it and, using the same leads, plug the other in and it's not noisy, then as Rob ^ says, the problem lies with the speaker, even if the monitor is the source of the interference.
 
If you got an identical one that is silent, then the humming one is faulty.

But, if NOT identical does the 'not humming' screen* have a 2 or 3 cable?

*keep getting confused with "monitor" speakers which of course are THE most common reason for a ground loop.
 
But, if NOT identical does the 'not humming' screen* have a 2 or 3 cable?

*keep getting confused with "monitor" speakers which of course are THE most common reason for a ground loop.

Yes . . . there are monitors and there are monitors. In this thread, the usage has mostly been monitor = screen, speakers = monitor speakers.

So OP has now two speakers, one which hums when the monitor is on, and the new speaker which doesn't.
 
Back
Top