EMI + Speakers / PC = Pulling my hair out...

oll3h

oll3h

oll3h

Associate
Joined
23 Oct 2012
Posts
405
So ive been trying to get to the bottom of this for what seems like forever and i am now coming to the end of my tether with it.

I have a pair of KRK Rokit 5 speakers that are connected to my PC and the cross talk and EMI is just driving me mad. When in Windows with the speakers on and connected to the PC the interference is there and noticeable but its nothing compared to when i try and play a game. As soon as the game starts up the noise is terrible to the point where i have to switch to head phones....something i've not really wanted to do in the heat we have had.

What i have tried;

  • New USB Sound Card
  • New RCA Cables
  • New power cables
  • Connecting the PC to one power source and the speakers to another power source in the next room
  • Connecting the speakers to a completly different PC
  • Unplugging all USB devices
  • Unplugging Audio header on motherboard
  • Disabling power saving in the bios
  • Ferite choke
  • Turning the monitor off/unplugging from the wall
  • Cursing lots
  • I've tried two different surge protectors
  • 3 different wall plugs

The speakers are perfectly fine when connected to a mobile phone which makes me think this is something to do with my mains supply :confused:

Can you get multigang power outlets with surge protection and EMI? Does anyone have any further ideas? I dont want to sell the Rokits as they really sound great but its looking like i may have to if i cant use them properly!
 

Marsman

Marsman

Marsman

Soldato
Joined
18 Oct 2009
Posts
11,175
Getting the same issue with two different PCs, while strange in that you wouldn't necessarily expect that, isn't beyond the realms of possibility that two different PCs have EMI problems. Depending on the components used, it can be relatively common.

I wouldn't expect it to be a ground loop issue between PC and speaker, because using a completely different mains socket elsewhere in the house for the speakers, I expect would get round that issue; unless noise is being introduced into the mains some other way. Maybe powerline networking?

If it were that though, then I'd expect you'd hear that noise wherever they are plugged into the mains, regardless of whether they are connected via audio cable to PC of any other mains powered device.

Increased noise when playing a game suggests it's EMI from the PC.

If you've tried a ferrite choke and got no joy; then that could be the same as one of these ground loop isolator's

Depends what's inside I guess. Some ground loop isolators use electronics, some maybe just a ferrite core.

If that's no good, then I think the next and possibly last thing to try would be a DAC that connects via optical. Optical uses light pulses, so has no electrical wiring for the EMI to carry along.

If your motherboard has no optical out, then either a cheap internal sound card with optical connection, or a USB one with optical output. Connect a cheap DAC with optical input from the jungle site.
 
Last edited:

oll3h

oll3h

oll3h

Associate
OP
Joined
23 Oct 2012
Posts
405
Cheers.

For how much they cost i am going to give the optical dac a go. Anything to try and remove this blasted noise!
 
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