Windows 7 Plagued with constant audio noise

Deckky

Honorable Member
I often record programmes from on-line radio but they are marred with constant audio noises in the background consisting of pops, clicks crackles and whistles. It seems to be worse when there's processor and network activity (like when recording) and appears to change when the display changes (noisier when the more detail there is on the screen). E.g. if you open a folder the sound goes kkkkk as the folder opens. I've tried to update the drivers but Device Manger says they're the most up to date available. I've also tried different power saving settings and disabled the processor throttling, some help a fraction but the noise is always there. I even tried disconnecting the mains earth to try and eliminate any earth loops but it made no difference. I did a latency check on the drivers and although it's high on ndis.sys, disabling the network adapter to eliminate the problem means I can no longer record anything (and with the adapter disabled there's still noise on the audio). Can anyone advise please as I'm nearly bald with all the hair tearing.


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Can anyone advise please as I'm nearly bald with all the hair tearing.
I'll bet you somebody can, if you'll post some information with respect the the gear you're working with, specifically I would guess the sound card you are using.
Since Windows Update is not a particularly reliable source of drivers there is likely another avenue to pursue but we'll need some specifics first.
 
Verify in the recording and playback properties whether any 'Enhancements' are checked. Uncheck those - if any.
 
System info is as follows...
Windows 7 Professional 32bit SP1
Intel Core i7 920
6GB RAM
Asus P6T mobo
AMD High Definition Audio
Realtek High Definition Audio
ATI Radeon HD 3600 Series
Front headphones connection
CD-ROM Drive
Realtek PCIe GBE Family Ethernet Adapter
Intel SSD 80GB
WD ATA Drive 1TB
IEEE 1394 Interface
Logitech wireless mouse / keyboard
Recording application - Adobe Soundbooth CS3 (no enhancements checked but the noise is present with no applications loaded)





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Thanks for the links, I've updated all the drivers associated with the P6T, including the ethernet adapter, but unfortunately there is no change in the level of noise.


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What about speaker location and/or possible 'bleed' from other sources?
 
I tend to use headphones all the time, plugged into the front socket on the chassis. There could be bleed or interference from somewhere, maybe the video card. Could a separate sound card help? Would be an expensive option if it didn't work.


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It's just that in your first post you mention how the noise gets worse if the screen gets busier. Have you tried moving the screen further away or isn't that an option?
A sound card may help although the onboard stuff nowadays is pretty good and besides until you've traced the source of the interference it's probably best to wait?
 
Yes the noise tends to change with amount of detail on the screen, less when it's blank but never silent. I thought it was more likely that it was to do with the sound card rather than the screen itself as the noise doesn't change if I turn the screen off. I didn't want to try and test this by disabling various screen drivers in case I loose all visibility to get it back again. During recording playback on Adobe Soundbooth I get repeated ch-ch-ch noises as the cursor steps across the screen but I don't know whether that's due to video interference or as a result of the processor being loaded. You can also see the repeated noise spikes on the recorded waveform.


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In keeping with Kemical's current train of thought, it's probably important to note that cable shielding is critical and that cheap, poorly shielded cable can produce all sorts of problems especially cheap HDMI cables. You may want to consider swapping out a cable and see if that might help.
 
Yes the noise tends to change with amount of detail on the screen, less when it's blank but never silent. I thought it was more likely that it was to do with the sound card rather than the screen itself as the noise doesn't change if I turn the screen off. I didn't want to try and test this by disabling various screen drivers in case I loose all visibility to get it back again. During recording playback on Adobe Soundbooth I get repeated ch-ch-ch noises as the cursor steps across the screen but I don't know whether that's due to video interference or as a result of the processor being loaded. You can also see the repeated noise spikes on the recorded waveform.


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Static and crackle are often caused by the connectors (loose/dirty/poor connection). Whistles are often ground loops. They happen when multiple wires are individually shielded and the shields are connected to ground at both ends of the cable. Proper practice is to use an actual wire for each needed circuit connection (not have the shield double as part of the circuit), have the shielding connected to ground at only one end of the cable, and have a single ground connection between the separate devices.

That said, if the noise changes with the amount of detail on the screen, the problem is likely related to the video. You will sometimes see a similar problem on your TV--the sound will have static when text appears on the screen (it is typically a problem at the other end, not your TV). From what you describe, the problem is at your end (noise related to what is happening on your computer, independent of the source programming). It sounds like some kind of video signal leakage. It's possible that your monitor cable is acting like an antenna and the signal is getting picked up by something in the computer's sound input, or the computer's video circuitry is going bad. See if the symptoms change when you move or replace the monitor cable. You could also try putting a ferrite core on the monitor cable at the computer end.
 
Many thanks for the suggests, the only audio cable in the circuit is on the headphones so as the noise varies with video activity rather than being a constant crackle that changes when I jiggle the headphones jack I assume that it's not coming from there. I disconnected the DVI-D cable from the back of the PC (no HDMI) to eliminate any cable radiation and the noise is still the same. I tried disconnecting the mains earth before to eliminate any ground loops and that didn't help so it looks like it's internal interference from somewhere.


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You didn't mention whether you have a microphone connected. A bad mic can produce the kinds of noises you describe. If you have a mic, disconnect it and see if the problem goes away.

One last thing to rule out: get some RCA plugs and mini-plugs, short out the contacts inside the plug (where you connect the wires), and plug them into all of the sound input jacks at the same time (microphone, aux sound input, any other your computer may have). If the noise goes away it means it is being picked up by one or more of those inputs. The mic input gets the most amplification and is most prone to generating noise.

If that makes no difference, it is likely either something failing in the video circuitry or a bad component or solder joint in the audio circuitry. It's a hardware problem, not a software or driver issue (unless some software is producing sound effects). A quick test: boot in safe mode. If it is not a hardware problem, it will likely disappear in safe mode.
 
Looks like it's a hardware problem as it changes with video and / or processor activity, if it was coming from an input would it be constant and unvarying? There's no noise in safe mode but then there's no sound of any kind, same as muting the volume. It may be a combination of different causes as I tried disabling the high latency network driver ndis.sys which helped reduce some of the crackle but the video noise was still there (and no good for online recordings). It doesn't seem easy to narrow it down to any specific device without replacing them one by one to see if the noise stops (I have no spares). Could the noise be from a drain on the power as the processor or video kicks in to make the the changes seen on the screen? Or maybe it's on the video card itself creating interference somehow, maybe to the sound circuitry through the power rails or by radiation? How could you prove it by completely disabling the video card such that you can still see the screen to be able to enable it again afterwards? Even if the noise does go off with the video disabled, does that prove that the video card is the source? It could be just a link in a chain. Tricky.


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Looks like it's a hardware problem

Yes.

if it was coming from an input would it be constant and unvarying?

No. If it is a bad mic, that could generate the kinds of noise you're hearing (although that wouldn't change with video activity). Open audio inputs could be picking up electrical noise leaking from video circuitry. That's why the cheap test of shorting them out to eliminate this as a candidate. If that works, you could solve your problem without finding the defect causing the leakage--just leave unused inputs shorted out. Also as a test, I would disconnect all audio inputs at the computer end just to rule out that a bad cable is acting as an antenna.

There's no noise in safe mode but then there's no sound of any kind, same as muting the volume.

Forgot about that. I'll have to think about a simple way to keep sound enabled but disable all other extraneous software sources to verify that the problem is hardware. It might be possible to do something like boot in safe mode and then manually activate the additional drivers and services needed for basic sound. That's usually tricky if you can do it at all because there are dependencies and they would need to be activated in the right order so each one has everything it needs to load.

It may be a combination of different causes

Even though you can modify or reduce the noise by disabling various software, my guess is that you are just affecting the symptoms. There is probably a single underlying hardware-based cause.

It doesn't seem easy to narrow it down to any specific device without replacing them one by one to see if the noise stops (I have no spares).

I'm guessing there are only a couple of things that are the likely culprit. Your video circuitry is top of the list. If it is on a separate physical card, you could swap it as a test, but that typically isn't the case except on laptops. The other is the motherboard.

Could the noise be from a drain on the power as the processor or video kicks in to make the the changes seen on the screen?

It's probably not being caused by the output of the power supply but I suppose it's possible that a defective capacitor in the power supply could be allowing the power pathways to serve as a conduit for electrical noise from another source. The odds are low for two simultaneous, unrelated hardware problems.

Or maybe it's on the video card itself creating interference somehow, maybe to the sound circuitry through the power rails or by radiation?

That's the most likely explanation.

How could you prove it by completely disabling the video card such that you can still see the screen to be able to enable it again afterwards? Even if the noise does go off with the video disabled, does that prove that the video card is the source? It could be just a link in a chain.

I believe video circuitry must be present to boot up. You could do something like add a PCI video card. As long as the existing video circuitry is receiving power, you could well still get noise if that is the cause, but if it is not processing the video signal, the noise wouldn't vary with the video content. That would be a smoking gun.
 
Wow, many thanks for that Fixer. I'll have to think about each one and try them out. I don't have a compatible spare video card to try but it may be worth getting a cheap one to test it.


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Glad you found this before replacing your motherboard. An audio driver with a flawed design would have been my very last guess given the symptoms. This is a good lesson to start with a search to see if other people have experienced the same problem and already solved it.
 
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