Squeeling through TV when PC running.

[rb6k]

I have a panasonic HDTV that I connect to my 512MB GeForce 8800 GTS 512 using a hdmi lead and a hdmi:dvi converter. (Graphics card only has 2 DVI ports on the back)

For the sound I run an auxillary cable from the tv's red and white jacks through to the headphone jack on the front of the PC.

Now this worked for over a year no problems and then all of a sudden there was a whistling sound coming through the channel we use for the PC.

I've tried replacing the wires and the converter- failed.
I've tried muting the sound input devices (mics etc) - failed
I've tried a different channel on the tele - failed
Its not the TV as I have my xbox, sky and wii all running through it too and none of them have a whistle coming through.
I've tried reinstalling the graphics cards software.
My PC speakers do not have this sound coming through them at their loudest.
I've tried running the wires a different away around the room avoiding electrical sockets, basically shorterning the distance and running each wire away from eachother/together, every which way I could think of around the room.


I'm almost certain its not an error on the tv, but if I take out the HDMI wire and just play sound the squeel stops. If I take out the sound and leave the video running the squeel stops. This suggested maybe some sound signal is being picked up by the HDMI wire which is confusing the Tele but since DVI doesn't output sound I figured not.

I at at my wits end to figure this out because it makes watching things through the computer a nightmare now. It just whistles away like a slight interferance sound regardless of wether anything is being played on the PC. I've disabled everything to stop it but it still seems to be sending some kind of signal to the tele.

I'd really appreciate your help on this, as it will probably show by the side I am new to the site (I was googling answers and came across your forum) thanks in advance!

Rest of specs:

Running Windows 7 64 bit
Intel Core 2 Quad Q9450 @ 2.66GHz
4.0GB Single-Channel DDR2 @ 399MHz
ASUSTeK Computer INC. P5Q PRO TURBO (LGA 775)
488GB Western Digital WDC WD5000AAKS-00A7B0 ATA Device
VIA High Definition Audio (onboard)

Anything else needed I'll find out.

 

[Twoboxer]

Once I read that it stops squealing when you remove the HDMI cable, my first thought was "feedback". The kind of squeal you get when you plug an open microphone into a PC playing music, and get an output-to-input loop. But, as you say, no sound over DVI. Unless . . . anyhow:

Have you tried disconnecting your PC speakers? Have you tried using the speaker jack (instead of the headphone jack) to feed your TV-sound? In either case, does the whistling stop?

Edit: And of course . . . what did you change (or Windows change for you lol) just before this started happening? Drivers etc?

 

[rb6k]

Hey Twoboxer, thanks for the reply!

I've tried putting the wire into the speaker jack and the same noise happens. It was a good shout though, when I thought of it I thought I had the problem licked!

Nothing changed on the system, the problem is this happened last year and I swear all I did then was disable the microphone jacks and it stopped. I checked that was still the case and sure enough it is so I have no idea why its happening or if I am just confusing what I did before with something else I fixed. Its had me at my wits end thinking about it because I can't think what I did to fix it.

I've tried uninstalling and reinstalling the graphics card drivers and the sound drivers to the computer. I've changed other drivers to try and fix it too.

The worst part in all this is I am an IT student, I've exhausted my knowledge, my class mates, my lecturers, now I'm here trying to fix it and everything we seem to try is a no go.

 

[Twoboxer]

You've tried lots of stuff that should have fixed the problem - no joy. Let's try some stuff that shouldn't fix it, maybe it'll work Ready?

Take a small length of "bell" wire and strip a small portion at each end. Attach one end so that it touches the ground portion of the jack you're currently using, eg headphone jack. One way to do this is to wrap one stripped end of the bell wire around the plug before you insert it into the headphone jack. Another way is to insert the jack almost all the way in, stick the bell wire in, and jam the plug fully in against it to hold it. Does that stop the whistle?

If not, leave the one end attached as above. Take the other end and touch it to the psu case and various metal parts of the PC case itself. Do any of those stop the squealing?

What I'm shooting for is insurance that the jack's ground is a common ground for the whole PC. It should already be a common ground, of course.

The other possibility is that two audio sources are feeding the same signal to the audio chip, or rather the same source is being sent twice, . . . but only when the HDMI cable is actually attached to the TV. (Because once you pull that cable the squeal stops).

Is it possible that you have selected settings that will (1) send audio over HDMI . . . system says wait, no HDMI . . . send alternate route and (2) automatically send an alternate, lower quality audio not over HDMI. The result being you get two signals at the audio chip, slightly out of phase, which stops once the system senses the HDMI cable is disconnected (stopping (1) above)?

If that's the case, stop one lol.

Geez, these sound like silly suggestions lol.

 

[rb6k]

Those look like good replies to me! I'm not sure what bell wire is to be honest so right now I am trying the 2nd idea whilst I figure out what to do with idea 1. The idea that it is sending 2 signals was what I considered when taking 1 wire out fixed the problem so hopefully this is the right direction to go down.

I disabled "HDMI Output" on sound settings, that hasn't made the whistle go away. Is there any other sort of setting like that hidden somewhere that I can change? I had a look at the media player, but I've even tried using 4-5 different ones to fix it with no results. I've reinstalled drivers and all sorts but theres probably just 1 hidden button or setting to change that sorts all this easily.

Thanks again for your indepth reply!

 

[rb6k]

I've just tried going into my BIOS and disabling "high definition audio" and the noise has gone, but of course so has the sound on my PC. So that surely narrows it down somewhat to being an issue with the sound output? I think what you said about the pc not being able to find a HDMI so redirecting it to the front panel must be right.

What to do now?

 

[iam2thecrowe]

so if you plug in other speakers or headphones is the noise still there? if so then your sound card/onboard sound is the most likely cause.

 

[Twoboxer]

I guess i'm too old lol. "Bell" wire is just simple, 18gauge or higher (smaller diameter) electrical wire. A piece of telephone wire - one strand - would work. What I was trying to do is connect the groun portion of your jack to the grounds used by the rest of the system using that piece of wire.

It shouldn't work, because the problem exists in two jacks - the odds are bad that both have become ungrounded . . . but I was reaching.

Disabling Hi-def audio just disables the audio chip. While it eliminates the squealing, its impact is a bit greater than that lol.

 

[rb6k]

The noise goes away if I plug in other speakers/headphones, it seems to only exist in this set up arrangement and it didn't exist in that for a while.

Would disabling the chip have ruled out bad grounding? I'll have to have a go at the wire later.

I'm considering getting a cheapo sound card just to sort it out but I don't want to go out and do it if its a silly problem.

 

[iam2thecrowe]

if it is working through headphones, then its not the sound card........Disabling the sound chip just disables any output and doesnt really rule out anything. Next step is to look at the cable from sound card to TV. And it may be something else providing interference along the cable. Try running the cable away from all other cables. If its not that then its the TV itself.

 

[rb6k]

I tried running the cables away from everything else, and I tried a seperate route for each one etc.
It can't be the tele, it doesn't have interferance with sky/xbox/wii and I've changed the ports etc, its only if HDMI and Aux cable are both in at the same time so something somewhere is sending 2 signals or something.