Static in audio speakers - running out of solutions

[aoxx]

Hi,

This has been a grueling week and I'm pretty much stuck. The problem is that I moved into a new flat and whenever I connect my speakers to my desktop computer, they produce a very loud, persistent static which makes them unusable. The setup used to work fine at my previous home! My monitors are active Yamaha HS7. Here's all the troubleshooting I've done, based on advice I could find online so far:

- The character and intensity of the static varies with computer activity, e.g when moving the mouse, CPU computations, updating the display, etc.
- The static is also present, albeit less intense and chaotic, when browsing the BIOS menus
- Disabling all power savings features in BIOS didn't help
- Speakers are quiet if they're not connected to an audio interface
- Speakers produce clean audio when connected to my laptop, whether the charger is attached or not
- Plugging the computer and the speakers into various sockets around the flat and changing their relative locations doesn't improve it
- Using either the front panel, or the rear panel output from the onboard audio doesn't improve it
- Tried using two different external USB-powered audio interfaces, no improvement
- Tried using a separately powered amplifier connected to the output of the onboard soundcard, no improvement
- Tried routing audio via the HDMI output of the discrete GPU card, hooking up an HDMI monitor, then connecting the speakers to the audio output of the monitor; no improvement

All this seems to suggest that any audio interface connected to the computer, regardless whether it is powered separately or not, regardless whether it takes digital or analog input, is receiving this electric discharge, which then travels across the audio cable and into the speakers. This is all the more bizarre since the setup used to work fine at my previous flat. I guess sending the audio wirelessly to an audio interface is possible, but it would introduce unacceptable latency for my needs. Can anybody please help me troubleshoot this further?

 

[amirm]

This is the classic ground loop/noise when computers and audio gear are involved. One solution is to use optical out from the computer. You run that to a DAC and then the rest of the audio system. When you used an audio interface, did you use balanced connection to the Yamaha? That should be much more immune to this problem.

 

[aoxx]

This is the classic ground loop/noise when computers and audio gear are involved. One solution is to use optical out from the computer. You run that to a DAC and then the rest of the audio system. When you used an audio interface, did you use balanced connection to the Yamaha? That should be much more immune to this problem.

Hi, and thanks.

My understanding was that ground loop typically results in a "hum" at a constant, low frequency; but in my case, the static is buzzing chaotically all over the frequency spectrum, and at various intensities, correlated to computer activity.

I guess optical could be a solution. That's because it doesn't transmit electricity, right? So maybe it wouldn't carry over the problem to the DAC. The budget friendly DAC with toslink input on amazon is the infamous Prozor (video review), and since that video I've been really scared to buy a cheap DAC. Clean audio is really important for my needs.

I've been using unbalanced cables, because I don't currently have an audio interface with balanced outputs. I was really hoping to fix this without a substantial equipment upgrade, especially since it used to function correctly before. Any idea what could have gone wrong, to make such a dramatic difference? I guess I could try borrowing an expensive interface and balanced cables, just to test it out.

 

[MaxwellsEq]

My understanding was that ground loop typically results in a "hum" at a constant, low frequency; but in my case, the static is buzzing chaotically all over the frequency spectrum, and at various intensities, correlated to computer activity.

The hum and buzz is the experience you get with "classic" analogue electronics and ground loops. If you read a few threads on here, you will discover that computer ground issues can result in static and crackling types of noise sometimes louder with heavy GPU usage or mouse movements.

 

[aoxx]

The hum and buzz is the experience you get with "classic" analogue electronics and ground loops. If you read a few threads on here, you will discover that computer ground issues can result in static and crackling types of noise sometimes louder with heavy GPU usage or mouse movements.

I see. I've been reading as much as I could, on this forum and others and sometimes the information is conflicting. I've also been trying a lot of suggestions already, which makes it frustrating that I didn't make any progress. How should I try to fix/mitigate the ground issues? Most people out there are able to enjoy their active speakers with just a basic computer build. So it feels like something very specific went wrong with my setup/grounding, perhaps something I could correct without having to invest into expensive interfaces and cabling.

Thanks

 

[ozzy9832001]

I'd also make sure they wired the outlet right and it's not a hot neutral.

 

[MaxwellsEq]

The problem with grounding issues is that they are always your specific problem! The issue is unique to your house, equipment and cabling.

In professional studios, differential/balanced working is normal to minimise the lottery of earth issues.

The first approach to fault finding is to work out what has changed, but since you have moved location, that is a lot of variables.

I would start with a simple mains tester that can show whether live and neutral and earth are correct in the sockets you are using. It's possible they were wrong in your old house (e.g. a missing safety earth).

The simplest way to eliminate earth issues is to put a fibre connection in place.

 

[audiofooled]

Is it possible that during transport the desktop received some kind of a bump? Sometimes it takes as little as some of the motherboard stand-off screws getting loose or possibly in the PSU. Or any of the internal connections for that matter. You could also try BIOS settings related to Spread Spectrum.

 

[AnalogSteph]

I've been using unbalanced cables, because I don't currently have an audio interface with balanced outputs. I was really hoping to fix this without a substantial equipment upgrade, especially since it used to function correctly before. Any idea what could have gone wrong, to make such a dramatic difference?

I would also suspect something along these lines:

I would start with a simple mains tester that can show whether live and neutral and earth are correct in the sockets you are using. It's possible they were wrong in your old house (e.g. a missing safety earth).

Ground loop issues in a setup like yours normally ought to be near-inescapable. I ran something similar for years, and while I was able to reduce the noises to an acceptable level by turning down input sensitivity, they never went away entirely until the Great Cabling Makeover, whereupon a Behringer HD400 was introduced and dubious-quality adapters were eliminated along the way. Since then, cabling has been 3.5 mm to 2x TS --> HD400 --> 2x TRS to XLR male. Going back to onboard audio has reintroduced some mild clicks whenever the fridge is turning on or off, but other than that, silence.

So a "substantial equipment upgrade" is not actually needed.

Now there's just one thing that has me confused: A flat is generally a UK term, but to my knowledge ungrounded outlets should generally be a thing of the distant past there, and the writing style doesn't exactly scream Brit either. So where are you from, OP? (My guess would be Scandinavia or the Netherlands.)

 

[Hayabusa]

a lower restance earth connection between your audio interface and the speakers could help. try to make a temporary connection to see were the issue is, do you have good 'bannana plug' cables for for instance a multimeter?

 

[aoxx]

Hey guys,

Sorry for the late reply. The experience was really stressing me out, so I gave up trying to find the root cause. I ended up creating a direct ethernet connection between my desktop and my macbook and using it to stream PCM 16bit audio. As I mentioned, when speakers are connected to my macbook, there is no noise. I posted a longer description of this workaround here: https://gearspace.com/board/showpost.php?p=16597500&postcount=8. This was also a cheap solution, even cheaper than buying a hum destroyer, as someone suggested. And definitely cheaper than a high quality, clean DAC for an optical setup. The only downside is a bit of latency, which is actually under 10ms and practical for my needs.

Happy to hear more suggestions if people want to share. Perhaps this post will be useful to anyone else trying to troubleshoot a similar problem.

> whereupon a Behringer HD400 was introduced

Did you notice any changes in sound? I heard that this kind of device alters the analog signal enough to make the sound different, but I'm not sure if it's true.

> Now there's just one thing that has me confused: A flat is generally a UK term, but to my knowledge ungrounded outlets should generally be a thing of the distant past there, and the writing style doesn't exactly scream Brit either. So where are you from, OP? (My guess would be Scandinavia or the Netherlands.)

You're right, I live in the UK and have the standard, grounded sockets.

 

[AnalogSteph]

> whereupon a Behringer HD400 was introduced

Did you notice any changes in sound? I heard that this kind of device alters the analog signal enough to make the sound different, but I'm not sure if it's true.

Well, at least the RMAA loopback measurements that I took years ago with my soundcard at the time (an Audigy FX) didn't indicate any noteworthy frequency response aberrations or undue distortion at ~1 Vrms levels. I should probably repeat those at some point. If memory serves the HD400 had something like 2 dB worth of insertion loss, and one direction appeared to load down the output more than the other (something that can drive 600 ohms comfortably is definitely recommended), but other than that it seemed sufficiently transparent in this application.