Odd "buzzing" noise when anything is moving on screen.

[JosephLeo]

Hey guys, got an odd one today. One of my clients called me about a strange buzzing noise anytime they move something on the screen and the more stuff there is moving the more louder the noise (e.g. moving the mouse sounds like a fly passing by, whereas a movie sounds like a vuvuzela)

I tried checking the audio settings, enabling and disabling certain things like CD Audio, Line-In, or anything that can cause interference. I then suspected it was the graphics driver since it only happens when things move around the screen and that was no help and then I decided to check if it was the speaker wire itself so I tried a different set of speakers, and still no help there. Finally I checked to see if there is any "wireless interference" so I unplugged the wireless network adapter and used a wired keyboard and mouse and still nothing.

The system is as follows:

Motherboad: ASUS P5GC-MX/1333
CPU: Intel Core2Duo E7400
GPU: ATi Radeon HD 4850 (512MB)
OS: Windows 7 Home Premium 32-Bit
Audio: Onboard

Another thing: this problem goes away when I run the audio through HDMI. Unfortunately the client doesn't have an HDMI capable monitor.

Any ideas what the problem could be? At this rate I think I'm going to sell this guy a sound card.

 

[Thedog]

If its a desktop and a soundcard fix it then do it. A soundcard is like 5 bucks so whats the point in troubleshooting further if that would solve it.

 

[vdub12]

It sounds to me like the on-board sound might be going out to.

However, I don't know why the noise would change depending on the size of the file being moved. Thats just weird.

Try to boot a Linux live CD and see if it still does it.

 

[JosephLeo]

It sounds to me like the on-board sound might be going out to.

However, I don't know why the noise would change depending on the size of the file being moved. Thats just weird.

Try to boot a Linux live CD and see if it still does it.

It's not based on the file size, it's based by the amount of movement on the screen. another way to explain it is if I open up a blank notepad and resize it to about half the normal size it would make about half as much noise as it would when I move it around.

 

[norm1320]

I had this problem twice. Once with standard vga cables, fixed by adding extra ferrite ring at each end. And once with and HTPC setup with VGA to RCA for video and minijack to RCA for audio, fixed by adding ground loop isolator on the audio line.

 

[mooncat]

is this noise coming through the speakers or is it from the pc tower? I just had to RMA a Corsair power supply that would buzz anytime you engage the software, like scrolling, or typing.

 

[vdub12]

It's not based on the file size, it's based by the amount of movement on the screen. another way to explain it is if I open up a blank notepad and resize it to about half the normal size it would make about half as much noise as it would when I move it around.

I see. I thought you meant the size of the file made a difference.

I have to agree with another poster I think this is interference, try another monitor cable, use one thats shielded.

Make sure the one you use has the round isolator on it like the photo below.

 

[JosephLeo]

I had this problem twice. Once with standard vga cables, fixed by adding extra ferrite ring at each end. And once with and HTPC setup with VGA to RCA for video and minijack to RCA for audio, fixed by adding ground loop isolator on the audio line.

Tried swapping the VGA cable, but to no avail. However, the ground loop isolator worked, just so happened to have one lying around my misc. adapters bucket. It's not a pretty fix, but it's a fix. Unfortunately for me the customer doesn't like things like adapters like this, dealt with him a few years ago back when I was doing this stuff for free. I'll tell him about the fix, but try to sell him a new sound card. Thanks for the help.

is this noise coming through the speakers or is it from the pc tower? I just had to RMA a Corsair power supply that would buzz anytime you engage the software, like scrolling, or typing.

The sound is coming from the speakers.

I see. I thought you meant the size of the file made a difference.

I have to agree with another poster I think this is interference, try another monitor cable, use one thats shielded.

Make sure the one you use has the round isolator on it like the photo below.

Nah, it wasn't that. Norm figured it out. I still don't understand the cause, but I now know the fix. Oh well.

Anyone have any ideas what can cause this error?

 

[norm1320]

The cause is EM fluctuations in the VGA cable inducing current into the audio cable. This being the case, switching sound card probably will NOT fix it.

edit: Repositioning the cables MAY help though. If you can keep the VGA and audio cables as close to perfectly parallel to each other as possible, you reduce (but not eliminate) the source of the problem.

2nd edit: You could also try a couple of split ferrite cores if you have any around. Just add one to each end of the cable, near where the built-in cores are. Something like this: http://www.olympixcorp.com/rfchoke/ferrite.htm