Click here if your desktop/laptop audio contains strange noises

[Martin Walker]

Hi again Will!

The Nio is bus-powered, so the only mains earth connection is likely to be from your laptop. Since you’re listening to the Nio output directly using headphones, and have no other mains-connected gear attached, then I reckon it’s impossible for you to be suffering from a ground loop, which requires at least two connections to mains earth to complete the loop.

To answer your points, the function of a DI box is to break an existing earth loop, and with your described setup I no longer think you have one.

In fact, the thought occurs that perhaps your laptop isn’t earthed at all i.e. has a ‘figure of eight’ mains plug/socket and an oval rather than circular mains cable. If this is the case then the noises you’re hearing may simply be that NOTHING is earthed - guitars in particular can pick up all sorts of nasty interference noises unless you earth them.

Andy has arrived ready for any guitar-based advice, but in the meantime I’d try plugging in a cable to any of the laptop’s unused sockets and then touching the outer metalwork of the plug (NOT any of the pins inside the plug) at the other end of the cable to a nearby earthed object such as a radiator (find a bare metal bit). if your noises go away you need to create a more permanent earthing cable.

Good luck!

Martin

[buggymusic]

The ART hum remover box didn't do it for me

Made the hum worse actually

-1

[ef37a]

Just FWIW.

I was sat with Fluke DMM and HP G6 power supply and decided to check mains earth pin to DC out neg'.

One million Ohms (1.01M actually). Is light and reason therefore begining to dawn?

Dave.

[Martin Walker]

Yep - that’s what my ancient Clevo laptop is like, and its metalwork also feels ‘furry’ to confirm that it’s not connected to mains earth in any way until you plug it into another earthed item such as a mixing desk or amp

No ground loop problems though

Martin

[jamesmorison2011]

This topic help me to fix my problem.
Thanks guys

[Martin Walker]

Yay - another satisfied customer

Martin

[Ash55]

I laughed a little bit because of the title of the topic, but it's so true! Sometimes I just get strange noises out of the boxes and I wonder why this is happening. But I'm not an expert in trouble shooting, therefore I always need help from experts, who fix it for me! Thanks for the nice recommendations in this thread.

[Mark Henry]

Few months back, there was a funny noise in my laptop. I think the problem was due to earthing. As soon as a I found some hint about the problem, I change my adapter to other plug, after that the sound stops.

[ef37a]

http://www.elektor.com/news/usb-isolator-prevents-ground-loop-problems.2052044.lynkx?utm_source=UK&utm_medium=email&utm_campaign=news

This ^ just caught my eye, have not even read up on it yet but I would make one observation.

My V old HP laptop makes a horrible noise running into a pc outputting audio from a usb AI when using the charger. I butchered a usb lead to remove the shield and that did diddly squat to cure it! Ok on battery power so deff' an earth loop.

Caveat whatsit!

Dave.

[Martin Walker]

Hi Dave!

'emptor' is the word you're searching for

I suspect that USB isolator will be mighty expensive

Just checked and it's not as bad as I expected: 84 Euros + VAT

www.cesys.com/en/products/kategorie/signal-processing/produkt/usb-isolator

Martin

[ef37a]

Hi Dave!

'emptor' is the word you're searching for

I suspect that USB isolator will be mighty expensive

Just checked and it's not as bad as I expected: 84 Euros + VAT

www.cesys.com/en/products/kategorie/signal-processing/produkt/usb-isolator

Martin

Yes, knew that, being silly.

Expensive if it does not work! As I say I open circuited the shield on a cable and it did not cure the loop problem. Is this device more than just a "braid breaker"?

I suspect the loop is formed by the DC return and so the only way to break that would be a DC-DC converter and since such devices are only about 80% efficient this could cause problems with some AIs?

Dave.

[SilentMind]

Hi folks,

My i7 Desktop home-brew pc is makin two kinds of strange noises ... both sharing the curious problem that they are entirely uneffected by changes in soundcard / DAW volume changes. I am monitoring the sound via headphones plugged straight into my soundcard (RME AIO).

Here's the two kinds of noise :

1 > A very quiet kind of fuzzy high-freq interference that dances in time with mouse movements + computer activity. The most annoying of the two as it quietly fuzzes at me when I'm doing all those DAW things that dont involve listening to the music. Aaaargh, I can hear it now.

2 > A quiet high-pitched 'test tone' type wail added only when monitoring a live input. I am running unbalanced signals throughout (the RME card has optional balanced signal expansion that I'm considering).

The only equipment plugged into the mains at the moment is the pc, monitor and cable modem. I've rebuilt the pc at the weekend, tried different soundcards / graphics cards / power supplies and the noises remain.

I've read the thread but cant see anything quite like this described as a ground loop. Friends think I'm mad as the noises are pretty quiet but they're driving me slightly nuts, I'm a 35yr old with a history of tinnitus so should, in theory, be the last person to moan about strange persistent noises in me lug-holes.

Any advice greatly appreciated before I resort to violence!

[ef37a]

Silentmind, you have a monitor. Does that perchance take an earthed IEC plug?

If it is powered from a line lump does the lump have a 3 core main lead and if so unpug it and check for earth continuity from mains plug earth to sleeve of the DC power plug.

You say " Wail when monitoring a live input". Input from what and is it earthed?

Never mind the proles that call you nuts! We have come a long way and paid very good money for -100dBFS noise floors (I am not quite there yet but I do get -93dBFS and no waily/buzzy noises!). You want it right!

Have you emailed RME? I would think they are helpful people (like Quad, A&H and CTH the "top people" usually are)and might have found an incompatibility with something in there? And download Right Mark analyser, that will give you a graphic picture of the problem.
BTW RM, Don't like the re-vamp. If it ain't broke!

Dave.

[funkinlesson]

I hope someone can help me diagnose this problem with my desktop machine.

I am getting unwanted noise via the line in on my on-board sound card which has the output from a DJ mixer connected to it. If I am monitoring the line in and I turn my speakers up loud, I can hear a kind of ticking noise and a high frequency tone that keeps changing in pitch. This happens even if my mixer and turntables are switched off, so there's nothing going into the line in and in theory I should hear nothing but silence.

I bought an internal PCIe card thinking that this would solve the problem as I assumed that the on-board sound card was just poor, but it didn't. As soon as I clicked the button to monitor the line in, the ticking/high frequency noise can be heard when the speakers are turned up loud. The on-board sound card was disabled in the BIOS at this stage.

In both cases, as soon as I stop monitoring the line in, the speakers are silent when the volume is cranked up.

Specs of my PC: -

Maximus IV Gene-Z/Gen 3 motherboard
Intel Core i7 3770K CPU
16GB of Corsair RAM
Corsair 620HX modular PSU
Samsung 830 128GB SSD
Hitachi 2GB HDD

It's running Windows 7 Professional 64 bit with all of the latest patches/drivers/firmware/BIOS installed.

Thanks in advance!

[Martin Walker]

Hi funkinlesson!

This does sound like a digital ground loop problem – the symptoms you describe are exactly what you'd expect in such a situation. However, the specs of your PC are largely irrelevant – what you need to do is follow the more general and extremely systematic 'tracking down ground loop problems' Q & A that I wrote for SOS July 2005:

www.soundonsound.com/sos/jul05/articles/qa0705_1.htm

This will determine the gear item that's the culprit, and then you can use the advice elsewhere in this thread to cure the problem.

Good luck!

Martin

[funkinlesson]

Thanks for the reply, Martin.

I have a question - Assuming that a ground loop was the cause, would this still happen if I used an external sound card instead?

I started off by using the on-board sound and that gave me interference. I bought a couple of internal PCIe sound cards and they both suffered with the same problem. I then switched to an external USB sound card and the interference went away. Would that rule out a ground loop as being the issue, because would it not affect the external sound card if that was the cause?

Many thanks!

[Martin Walker]

No, sadly it makes no difference if the audio interface is a card inside your computer or in an external enclosure.

All that matters as far as ground loops are concerned is whether two or more devices are each connected to mains earth, and then how their audio is inter-connected.

That's why a step-by-step approach to isolate the culprit(s) is the only successful way to proceed

Martin

Martin

[Hugh Robjohns]

I then switched to an external USB sound card and the interference went away. Would that rule out a ground loop as being the issue...?

No, it just indicates that the external sound card was better designed.

Ground loops are an inherent fact of life. Most equipment employs a mains safety earth, mains socket earths are always joined together, and most audio interconnections involve an earthed screen -- so 'ground loops' will always exist.

The problem occurs when the current that inevitably flows around such loops is allowed to influence the reference ground of the audio circuitry, because it then becomes audible.

There are ways of minimising the current flowing around the loop -- such as plugging all the equipment into power strips fed in a start formation form a single wall socket -- or of breaking the loop by isolating the screen conenctions directly or via transformers. And such techniques usually render the unwanted hums and buzzes inaudible.

But fundamentally, well designed equipment using balanced connections shouldn't suffer from the problem in the first place. Sadly, there is still a lot of less than perfect equipment around.

hugh

[The Telenator]

"Click here if your desktop/laptop audio contains strange noises"

Martin, I'm probably kidding myself, but I prefer to call mine 'music'.

[Martin Walker]

That of course is your prerogative Telenator - you are of course at liberty to post a link to your 'music' so that we can give you a second opinion

Martin

[shufflebeat]

I've just retired my old XP lapdancer in favour of my Son's Vista model which was suffering from predicted headphone output damage. I hooked up a FastTrack USB and on to the little KRK's absent mindedly without the usual transformer isolator and was immediately confronted by...

...sweet, sweet silence.

No buzzing, humming or trackpad induced ants running up and down my power cable.

It's unnerving, I'm not sure if I should be doing something. It's like when the hiccups finally stop after an hour.

[biteater]

I'm having noise issues with a laptop and usb audio interface, but the noises are only apparent when connecting a guitar or bass to either of the DI inputs on the interface. I uploaded an mp3 to demonstrate the noises. You might need to turn up your volume.

https://www.box.com/s/ba46ea2ead932a8d0f33

0 seconds - Touching the laptop metal body, guitar bridge, guitar strings
6 seconds - Psu disconnected
10 seconds - Psu reconnected - gets a little quieter than before disconnecting psu
14 seconds - Hovering guitar inches over laptop body

This is very annoying. If anyone knows what the problem might be, please spill it. I'm grateful for any help. Also, things get a little quieter when the laptop is in super energy saver mode (Lenovo).