Humming & buzzing in monitor speakers from graphics card

[paroxsitic]

I just bought this PC from ebay. It originally came from IBuyPower 2 months ago.

The PC has Asus-P8Z68-V motherboard (not Pro)

It has a EVGA superclocked Nvidia GFX 560 Ti and I have a Sharp Aquos LC32D41U 32 HDTV. The LC32D41U only supports PC through its DVI connector (for some reason they don't let PCs use HDMI in 1:1 ratio mode for 1360x768).

I was already aware of that the HDTV couldn't do PC through HDMI has this setup worked fine with my old dell.

I hooked up the DVI cable to one of the two DVI females on the graphics card. I have an audio cable connecting my DVI audio from my HDTV to the green colored (line-out/headphone) motherboard audio jack in the back. No other color works but green.

When in 3D mode it gives the monitor's speaker a certain humm or buzz depending on the graphics intensity going from a high pitch squeal (light intensity reaching 3900 FPS) to a low humm (high intensity DX10 reaching 50 FPS).

When not using a 3D application there seems to be super faint noticeable high pitch buzz, that is only heard when the TV volume is really high.


Update:

Suspecting a ground loop but then tried....

My monitor is actually a HDTV and it has a 2 prong power cord anyways but I still plugged it into a completely different socket and the sound persisted. I then attempted to make a shield from alumnium foil and I could not get the sound to stop. Finally I played around with the wires and still the sound. Now I have the EVGA connected to my HDTV using DVI and I have a DIV audio cable from my HDTV to the line-out on the motherboard. You would think disconnecting the DVI would leave the sound but get rid of the picture but the humming stops when I disconnect the DVI. This leads me to believe the card is somehow trying to giving the DVI cable interference down the line. It's a expensive heavy & thick cable DVI cable with a male single link DVI-D end.

What is going on here?

Here is a person with the same CPU ,GPU and motherboard as me having the same issue: http://www.evga.com/forums/tm.aspx?high=&m=1216213&mpage=1#1420828



Update 2:

Decided to focus on drivers.

Installed the lastest onboard sound driver, retarted..same problems. Decided to reinstall the newest nvidia drivers, same problem. Decided to uninstall everything nvidia, restart, and now I can't run anything 3d to test (haha) as its generic driver. Reinstalled just the display drivers, not the audio....same problems.. Then I disabled all each audio device in device manager one by one and test, even with all audio devices disabled the sound persisted. Keep in mind this sound comes through even when I have the windows (software) volumne muted.

I am out of ideas driver wise.


Update 3:

I found another male to male 3.5 mm stereo jack and tried it, the sound still remains. Because the sound doesn't exist without the 3.5 mm jack by itself nor does it exist with the DVI by itself I am thinking this is more and more a ground loop issue. I might pickup a ground loop isolator later on...

I also found another thread:

http://www.overclock.net/t/1097243/asus-p8z68-v-pro-audio-problem-help-plz

and many many more, most all of them dealt with this problem using the different versions of asus-p8z68.

Many people suggest a PCI sound card but that solution seems to only fix it 50/50. The ground loop isolation seems to have better success ratio.

What do you guys think?

 

[tlmck]

Is the output ohmage on the PC matching the input ohmage on the TV? In other words, the PC output may be over driving the TV input.

 

[paroxsitic]

Is the output ohmage on the PC matching the input ohmage on the TV? In other words, the PC output may be over driving the TV input.

I assume I test this using a multimeter. Don't have one right now but come to think of it I should buy one for future occasions. I am going to get this one http://www.amazon.com/Sinometer-Manual-Digital-Multimeter-MS8268/dp/B000JQ4O2U%3FSubscriptionId%3D02B7Y8VZ2ZRE5MXHPMR2%26tag%3Dbestcoverycom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB000JQ4O2U

 

[tlmck]

I am not familiar with that brand, but I guess it is as good as any. I know Sears had an inexpensive Craftsman that used to be pretty good. I still have my trusty old Fluke I have had for years. Heck, i even still have my old Beckman I got in tech school back in the mid '80s. I would not trust it for critical measurements, nut it is still pretty accurate for measuring batteries and such.

You could certainly take a measurement, but I was referring more to looking up the specs for each device. The ASUS site is down right now, and I could not find the TV, even on Sharp's site. I would assume such info would be in the manual, but it is not in mine.

 

[paroxsitic]

I got the multimeter today, no idea how to use one. How can I check for a ground loop?

I couldnt find any tests specific to this situation on google.

 

[tlmck]

You can check on you tube for related videos, but I found this that explains as well as I can. Scroll to the bottom to see the PC example, but it is basically the same principal for all devices. http://www.siber-sonic.com/electronics/GLooptest.html

I also found this interesting. http://podcastanswerman.com/groundloop/

 

[paroxsitic]

OK I got some external speakers and hooked it up to the line-out of the computer and I don't hear the audio coming through the external speakers. I then hooked up my laptop to the monitor and got no pickup of any sounds. So I think this confirms its not a ground loop, nor is it defective speakers in the monitor. Somehow the 3.5 mm combo with the DVI is causing it to pickup nearby sounds. I got my ear close to the PSU/GPU area and I could tell a very faint squeal coming from them that is the same sound on the monitor. Just to note, I don't have a microphone hooked up at all.

I am a little baffled as to the problem at this point.

Here is a YouTube video demonstrating the sound: http://www.youtube.com/watch?v=KfgevNK9JuU

 

[tlmck]

Since the video is DVI-i on all connections, and I assume you have a good quality cable with isolators on each end, I think we can eliminate that.

Which leaves us with audio. Somehow or another, the PC output is not compatible with the TV input. Since we only have one PC output that seems to work, the only changes we could make would be on the TV end. I could not get any info on the Sharp TV, but as I recall, that style has red and white RCA audio sockets on the back. If so, I wonder if something like this would make a difference? http://www.newegg.com/Product/Product.aspx?Item=N82E16882196091

edit: I would suggest buying that audio adapter locally as shipping from Newegg would at least double the cost.

 

[paroxsitic]

The red and white output are for input 4, which is an HDMI. The only thing for input 5 (DVI) is the DVI audio, which I am using.

 

[tlmck]

Check the manual again and see if the red and white aren't dual purpose, meaning they can be used as straight stereo jacks in addition to HDMI audio. I do not know about Sharp, but I have seen other TV's that are this way.

Honestly I have not seen a Sharp in a few years. They used to be king of all stores around here and now they seem to have disappeared. I do remember them having the best picture in the early days of LCD. I always looked for a straight monitor from them, but never could find one.