Electromagnetic Interference

24-05-2019 10:25am #1

Ok,
Hoping someone might have any ideas..
I recently built a PC..to be used primarily for music..
Intel i9.. gigabyte aorus pro..
Corsair case..

I'm getting chronic Electromagnetic interference in my speakers..
I initially thought it might be the graphics card..changed it..no joy..
Thought it might be the heatsink fan..changed it for a liquid cooler..no joy..

It seems to be somehow related to the processor.. Like, if I get it to do something it gets worse..

Google has me thinking now that maybe it's the case..

It's not mains hum.. it's more of a high frequency crackle..

Any help would be appreciated, thanks..

Metric Tensor · 24-05-2019 10:37am

Are your speakers fed from a discrete sound card or the in-built sound card on the motherboard.

I read before that the mobo sound connectors are very poorly shielded and subject to interference and worse than that again are the wires to the front case connectors.

If you're into sound you're probably way ahead of me on that stuff - but just in case!

Cuddlesworth · 24-05-2019 11:07am

The I9 series like their power at load.

Is everything coming off the same extension lead?

smuggler.ie · 24-05-2019 11:29am

Could it be this you referring to.
https://en.m.wikipedia.org/wiki/Ground_loop_(electricity)

24-05-2019 11:31am

The speakers are being fed by an external mixer/soundcard..

Yeah, they're all coming from the one extension lead (that's a fancy one that should cancel noise)..

Yeah, I'll probably try taking power from another room next..
I've ferrite beads on the way..dunno if they'll help..

24-05-2019 11:32am

smuggler.ie wrote: »

Could it be this you referring to.
https://en.m.wikipedia.org/wiki/Ground_loop_(electricity)

No..it's kind of a higher frequency..and not constant..

ED E · 24-05-2019 11:58am

Coil whine?

When my system at low idle its a right b1tch for it.

Venom · 24-05-2019 1:10pm

Deleted User wrote: »

The speakers are being fed by an external mixer/soundcard..

Yeah, they're all coming from the one extension lead (that's a fancy one that should cancel noise)..

Yeah, I'll probably try taking power from another room next..
I've ferrite beads on the way..dunno if they'll help..

How is the external mixer/soundcard connected to the PC?

24-05-2019 1:23pm

Venom wrote: »

How is the external mixer/soundcard connected to the PC?

Hey..via FireWire..
Just FYI, the mixer and speakers were working fine up until the day before with another computer, so it's definitely something to do with the build..

Tried moving around all the cards in the computer too..

TerrorFirmer · 24-05-2019 1:32pm

Could it be coil whine coming off the PSU or GPU when under increased load?

If it's only happening when you're actually giving the PC a workload I can't really think what else it would be.

24-05-2019 1:44pm

Ok.. googling it, it does sound like coil whine anyway..but would that be being picked up by the speakers?, or would it be coming from the computer?..

K.O.Kiki · 24-05-2019 1:50pm

Deleted User wrote: »

Ok.. googling it, it does sound like coil whine anyway..but would that be being picked up by the speakers?, or would it be coming from the computer?..

From the computer.
Try unplugging the speakers and running the same CPU load.

24-05-2019 1:53pm

Yeah,
No, it's definitely being picked up in the speakers..

(Well, I think so anyway.. I'll check again this evening..)

TerrorFirmer · 24-05-2019 1:54pm

Deleted User wrote: »

Ok.. googling it, it does sound like coil whine anyway..but would that be being picked up by the speakers?, or would it be coming from the computer?..

From the PC but coil whine can project itself pretty well, if you didn't know what it was, it can sound like it's coming from elsewhere.

It would be coming from the PSU or GPU, but if you said you replaced the GPU, it's unlikely (though still possible) to be that.

24-05-2019 2:01pm

Is the case metal ?
try connecting the pc case to the mixer case with a bit of wire and see if it goes away.

24-05-2019 10:28pm

Just had a look at it there now..
It's definitely being picked up in the speakers..
It's not there when they're off..
It's not there when the computer is off, and I'm playing something through the soundcard standalone..
It's not coming through headphones out of the soundcard..

I tried disabling c states and changing power settings in windows..no change..

I'll try taking the power from another room in a couple of days..the ferrite beads might help..

ED E · 25-05-2019 3:50am

Is it the Aorus Pro or the Aorus Pro WIFI? The wifi can be an issue on some DACs (Ive had it on Numark cheapos).

Are they speakers or are they active monitors? If you're outputting low gain RCAs and then amping heavily in the monitor then you could be really exaggerating any induced noise (which is inherent to non balanced links).

K.O.Kiki · 25-05-2019 1:45pm

It's not coming through headphones out of the soundcard..

So it's the motherboard's onboard sound sockets are not protected.
Probable solution: get a USB external DAC / soundcard, or use the internal soundcard.

25-05-2019 1:52pm

@ED E..It's the Aorus pro wifi..
I don't think the wifi really affects it though..
@KOKiki.. No, the soundcard is an external firewire mixer..
I changed out the cables too, they're pretty good cables on it now..
The mixer is amplifying it, and the speakers are amplified too..
But, yeah, it's definitely interference coming from the PC though..

ED E · 25-05-2019 5:50pm

Are you using RCAs (Phonos) or a balanced TRS/Nuetroniks etc? It sounds like the former and you'll need to rectify that.

25-05-2019 5:59pm

Hey..
No, I'm using the big jack to jack mono cables..
They're pretty good cables too..
Just to clarify too, the mixer and speakers aren't amplifying the noise, they're just the gain stages or whatever

ED E · 25-05-2019 6:10pm

Can you tell us what speakers you're using?

Electromagnetic Interference

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