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Buzzing in Computer Speakers

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Adam Sternberg
Buzzing in Computer Speakers
on Nov 9, 2016 at 9:45:23 pm

I've got a problem that is driving me absolutely crazy.

On my desktop computer I am running two computer monitors...a 4K display and a 2K display. The 2K display is replacing a dead HD monitor that I was using.

From my sound card, I am running a 3.5mm out to a small mixer on my desktop, which I like using so I don't have to fiddle with the annoying audio controls in Windows. The cable there is 3.5mm split to two 1/4" that go into the mixer.

From the mixer, I send two balanced 1/4" cables to two powered Rokit 5 audio speakers on my desk.

Here's the problem, with the addition of the new monitor, I am getting a loud buzzing sound in the speakers that never used to exist with my other monitors. The louder I turn up the volume, the louder the buzzing gets and it's pretty loud even with minimal volume.

The second I turn off the new monitor, the buzzing stops. I have tried plugging the split cable directly from the computer to the speakers, bypassing the speakers, and the buzzing is still there so I know it it's not the mixer.

Everything is generally plugged into the same circuit (it's in my home office) so perhaps it's some sort of weird grounding issue? The monitor company is out of Korea with no real US based support so contacting them will be a worthless endeavor. Any ideas on how to fix this? I'd like to keep this monitor but not if it compromises my audio. Any help you can provide would be appreciated. Thanks!


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Richard Crowley
Re: Buzzing in Computer Speakers
on Nov 9, 2016 at 10:27:35 pm

Please explain what "generally" means here: "Everything is generally plugged into the same circuit " Either it is or it isn't. I believe you are on the right track to question the powering scheme. I would be 100.000% sure that everything is plugged into the SAME power circuit (including ground). Even if you have to go out and buy a larger power strip to accommodate everything.

You may need to use an EXTERNAL audio interface, i.e. something where the digital audio comes out through USB and is converted to analog OUTSIDE the computer box.

---------------------------------------------------------------------------------
Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.


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Adam Sternberg
Re: Buzzing in Computer Speakers
on Nov 9, 2016 at 11:25:00 pm

Sorry, "Generally" was probably a poor choice of words. Yes, I'm sure everything is running into the same circuit. It's a home office I have setup in a second bedroom in the house so it would all be on the same circuit. I do have the monitor plugged into one outlet on one power strip and the mixer/computer plugged into a different powerstrip in a different outlet. I've tried mixing/matching and that doesn't seem to change anything.


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Bruce Watson
Re: Buzzing in Computer Speakers
on Nov 10, 2016 at 2:11:24 am

[Richard Crowley] "You may need to use an EXTERNAL audio interface..."

Yup. This solved a problem I had years ago. Had noise from my graphics card inside the case effecting the output of the audio card, also inside the case. Switched to an external headphone amp fed by USB, problem solved.


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Adam Sternberg
Re: Buzzing in Computer Speakers
on Nov 10, 2016 at 4:42:06 am

So get an external audio card? I didn't even know they made those.


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Adam Sternberg
Re: Buzzing in Computer Speakers
on Nov 10, 2016 at 4:48:02 am

Also, if I do get an external sound card, why would this fix the problem? The sound card would still be plugged into the computer via USB. Now to test this theory a bit, I unplugged the audio cable running from the sound card to my mixer and the buzzing did stop, so it definitely has something to do with it being plugged into the computer.


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Richard Crowley
Re: Buzzing in Computer Speakers
on Nov 10, 2016 at 11:34:08 am

There are test procedures for determining whether the interference is being conducted into the speakers through one of the three major routes:

  • PROXIMITY - Move the speakers and the monitor as far apart as possible while still connected. Does the interference reduce?

  • POWER - Compare operation with the speakers plugged into the SAME power outlet (or power strip) vs. a DIFFERENT source. Same experiment with the monitor, and with the computer.

  • SIGNAL - Does the interference reduce (or disappear) when you disconnect the audio cable at the computer end? At the speaker end?


  • Tests should be conducted with only the monitor(s), computer and speakers connected and powered. Eliminate everything else for the experiments to reduce spurious symptoms.

    ---------------------------------------------------------------------------------
    Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.


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    Adam Sternberg
    Re: Buzzing in Computer Speakers
    on Nov 10, 2016 at 7:39:07 pm

    To answer your questions:

    1. The speakers are about 6 feet away from one another. The monitor is in the middle of them.

    2. I ran an extension cord/power strip in from another room and plugged the speakers into that. The buzzing was still there. I plugged the monitor into the new power strip and the buzzing was still there. I plugged the speakers back into their original outlets and the monitor to the new power strip and the buzzing is still there.

    3. When I disconnect the audio cable (3.5mm to split/unbalanced 1/4 inch) the buzzing stops. Same goes for when I unplug the speakers.

    I'm starting to think maybe it's the cord running from the computer to the mixer...that 3.5mm to split 1/4 inch. If that cable isn't shielded properly that might be the source of this problem. So should I get a new cable and make sure it's shielded properly?


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    Adam Sternberg
    Re: Buzzing in Computer Speakers
    on Nov 10, 2016 at 8:04:41 pm

    Update!

    I unplugged the DVI cable from the computer with the monitor on and the buzzing stopped.

    So my thoughts are that the monitor is spewing crap back through that cable and that's causing the problem. So what if I got a new DVI cable with some ferrites on it? In theory, that should solve the problem, yes?

    https://www.amazon.com/Cable-Matters-Plated-DVI-D-Ferrites/dp/B007NJ3WI8/re...


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    Richard Crowley
    Re: Buzzing in Computer Speakers
    on Nov 10, 2016 at 9:55:22 pm

    Using a DVI cable with ferrite chokes on the end(s) certainly won't hurt anything. But it MAY or may NOT solve YOUR issue. You don't know until you try it.

    We don't know the quality or construction of the cable you are using for the audio signal (and presumably you don't know, either). Certainly getting a good-quality cable will protect the audio signal from your computer to your speakers. My favorite quote about cables: "A $200 cable sounds better than a $2 cable. But not better than a $5 cable."

    The distance between the speakers is not the issue. The distance between the speakers and the offending monitor IS the issue. While using the same cables, can you move the monitor far to one side, and BOTH of the speakers far to the opposite side? Does that diminish the noise?

    ---------------------------------------------------------------------------------
    Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.


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    Dennis Lynch
    Re: Buzzing in Computer Speakers
    on Nov 26, 2016 at 9:55:41 am

    Wow cool! My friend is facing the same problem.I will recommend this to her.


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