static/crackle/coil whine/interference problem

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vonbosch
Posts: 44
Joined: Wed Jun 10, 2009 6:43 am
Location: Scotland

static/crackle/coil whine/interference problem

Post by vonbosch » Fri Mar 14, 2014 12:29 pm

G'day all,

I recently bought new speakers and they have brought to the fore a noise problem which was just about bearable before. It is not the speakers themselves, rather that the speakers are very efficient in amplifying all noises, including this annoying thing!

The symptoms are a static crackle (more-or-less continuous but quite quiet) and a whining noise whenever the computer comes under load. That is the annoying part. Even moving the mouse does it - although I found that a different mouse reduces the volume of the annoying noises a bit. It is definitely coming through the speakers which, I believe, rules out 'normal' coil whine which would eminate directly from the coil in question (most likely my Seasonic X460 fanless CPU). So maybe it is some sort of interference?

I have tried:

* removing the VGA card (and using onboard)
* removing the sound card (and using the onboard)
* removing all superfluous USB peripherals (actually not quite, I never tested my fan controlled or SD card reader which are on motherboard headers)
* unplugging the front panel audio
* turning on the monitor and removing its power cable
* booting both Windows and Linux

But nothing worked.

The most stripped down setup I tried was:

* CPU (Athlon X3) and 4 Gb RAM (don't remember manufacturer)
* Gigabyte motherboard (don't know product number off-hand)
* Crucial M4 256Gb
* WD Green 2Tb
* Nexus Fancontroller
* SD card reader
* Antec P193
* SEASONIC X460 FANLESS PSU (likely culprit?)
* Err some fans and stuff (but turning the case fans off with the fan controller doesn't help)

So if it is a particular component the culprit should be in that list. Obviously I could strip it down further (and test with my old mechanical boot drive) and provide more exact details of the parts. But I thought I'd ask here and get the benefit of wealth of the spcr experience first...

Firstly, can anyone hazard a guess at what is going on?
Secondly, can this be coil whine if it is coming from my speakers? It somehow seems more like interference to me.
Thirdly, if I was to go further with swapping out stuff, what would be the first thing to test? (after first removing all non essental stuff like the fan controller etc) I guess the PSU? Could the mobo be at fault? And what about the SSD?
Fourth, something that just occured to me, could my new speakers (what are heavy duty, full range PA speakers capable of kicking out 900W of sound and probably have coil hefty coils) be interfering with the PC? I don't get the sounds when using other sources (eg laptop) and headphone sound ok but it did happen with other speakers.

It is weird and stressing me out, any help appreciated. TIA!

markanini
Posts: 163
Joined: Tue Jan 21, 2003 9:59 am
Location: Malmo, Sweden

Re: static/crackle/coil whine/interference problem

Post by markanini » Fri Mar 14, 2014 1:19 pm

It's not unusual for this type of interference to be picked up by sound card circuitry, especially with onboard audio. You're speakers are merely amplifying what's being fed into them. I'd suggest a higher quality sound card.

EDIT: Have you started using any 3G equipment(routers, phones) around your PC?

xan_user
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Re: static/crackle/coil whine/interference problem

Post by xan_user » Fri Mar 14, 2014 1:28 pm

sometimes the only cure for static from onboard audio jacks is a sound card, or external DAC.

did you try muting all inputs/mics?

markanini
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Joined: Tue Jan 21, 2003 9:59 am
Location: Malmo, Sweden

Re: static/crackle/coil whine/interference problem

Post by markanini » Fri Mar 14, 2014 1:59 pm

xan_user wrote: did you try muting all inputs/mics?
Good point. Also try to set max the volume at the sound card, this raises the signal-to-nosie ratio.

CA_Steve
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Re: static/crackle/coil whine/interference problem

Post by CA_Steve » Fri Mar 14, 2014 2:45 pm

I often find that it's a combination of poorly shielded cables and poor ground connections. For example, I get hum/whine when using the front panel connector on my R4 while I don't when using the direct motherboard connector on the rear case panel.

- So, the speakers are self-powered? Are they plugged into the same AC power circuit as the PC? If not, do so.
- An impedance/line level mismatch can easily cause these same issues. Are your speakers expecting line level inputs or speaker level inputs? Are you driving them with a line level output or a headphone level output?

vonbosch
Posts: 44
Joined: Wed Jun 10, 2009 6:43 am
Location: Scotland

Re: static/crackle/coil whine/interference problem

Post by vonbosch » Sat Mar 15, 2014 1:16 am

Hi guys,

Thanks for the quick respones. I'll reply to all in turn here.

@ markanini
The issue occurs with both the onboard sound and my Creative Audigy 4, so I am not sure a better quality sound card would help. Maybe something with shielding as my Audidgy doesn't have any shielding.
No new 3G gear in operation.

@xan_user
As I said before, it is not just the onboard sound, happens both with sound card and onboard.
I just tried muting *everything* in alsamixer and the Ubuntu sound settings and that didn't help. Can go through the stuff in Windows later.

@ markanini
Yes, maximising the volume on the PC minimises the problem but it is not enough. Also I need some volume control and the PC is the most convenient point to do it, so I can't have it maxed all the time.

@CA_Steve
Yeah, the cable between the PC and mixer is cheap and much too long and coiled up (more induction?). That could be the culprit, I'll replace it with a short, high quality one when I can. But the same cable works fine for the laptop.
The mixer itself is old and borrowed (so kind of unknown quality) but again I don't get the issue with other input sources, so I think it really originates in my PC.
About poor grounds, I have an antec case and a seasonic power supply, I would expect a decent enough grounding but maybe I am naive.
Yes the speakers are self-powered, and on the same multiway power adapter as my PC.
As for signal levels, I am on 'the green one" which as far as I can tell is line level. My mixer is set to 'line' instead of 'mic' on it's gain nob which should be the appropriate level, right?

Thanks for the input!

CA_Steve
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Re: static/crackle/coil whine/interference problem

Post by CA_Steve » Sat Mar 15, 2014 7:47 am

As for signal levels, I am on 'the green one" which as far as I can tell is line level. My mixer is set to 'line' instead of 'mic' on it's gain nob which should be the appropriate level, right?
PC audio s/w usually has an auto-detect utility that pops up when you plug in a new audio cable. Try unplugging from the "green" connector and replugging to get the utility to pop up and then set it for line out - just to make sure. You can also try another output from the PC and set it to line out just in case it's the green plug that has a poor ground connection.

vonbosch
Posts: 44
Joined: Wed Jun 10, 2009 6:43 am
Location: Scotland

Re: static/crackle/coil whine/interference problem

Post by vonbosch » Fri Mar 21, 2014 2:39 am

Hi all,

I just wanted to say thanks for your help and that I solved the problem. The solution was basically markanini's. I opened up my software mixer and maxed the treble and bass and played with some other settings. This basically gave me a good enough signal-to-noise such that I could set my amplifier amplification low enough that I don't hear the annoying noises but still have enough range in the PC master volume for most everyday use. And if I really need more power I can crank up the volume on the speakers or my hardware mixer and the annoying noises will be drowned out by my high-volume racket ;-)

Cheers and happy silencing :-)

Matt

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