Completely random and extremely loud popping driving me nuts

[Uniformis]

Just recently my Logitech G51 speakers, have started making completely random popping noises. They are connected to an Auzentech X-Fi Forte with latest drivers (9th September 2011). All of these I have been using without issues since mid-2009.

The first time it happened I wasn't doing anything in particular, just reading a website (not listening to music or gaming etc).

It started very briefly with just two 2-second instances of popping in a single day.

Two days later it seems to have gotten worse. I'll usually get two to three 30 to 40 second instances of sequential popping each day, no matter what I'm doing on the PC. They can happen in intervals of minutes to several hours, up to 5 hours or so. This is becoming very annoying/scary when I'm just reading something, listening to music or playing games.

Seems like only the front speakers (which are closer to PC + electrical connections) will produce the noise.

At the time this was happening I noticed in my Sound Settings that both Microphone and Microphone FP reported as capturing very LOUD noise, even though there are none plugged in. The Microphone source, even with no mic present, always captures some static/buzzing noise and some PC audio somehow (not to mention it also captures the sound of me tapping the PC case - this I didn't know was possible - it's like there's a small microphone inside the sound card itself?).

Even though the noise is being captured by recording sources it doesn't mean the speakers will reproduce it as well. It seems to take some time before they do, or they don't at all.

I've recorded the loud noise they captured:

#1 http://soundcloud.com/asclepius123/random-popping-noise
#2 http://soundcloud.com/asclepius123/random-popping-again
#3 http://soundcloud.com/asclepius123/random-popping-yet-again

I've read something as simple as a worn fan bearing can cause static and popping in the line? If so my PSU's fan has been squeaking now and then lately (it has been for some time now), but I never noticed any connection to the popping noise.

I cleaned all the dust between the wires, re-seated sound card, re-plugged all audio connections. Left only my UPS (which has both PC and Monitor connected to it) on with everything else off: still had an instance of the noise being picked up by the "microphone".

Anyone know what could be the source of this? From the sound samples do you think it's possible to determine the nature of the source (EMI, house electrical interference, PSU fan, CPU/Mobo, sound card)?

I think it's safe to say it's not the speakers at fault (at least directly), but either inside the PC or electrical. Though the complete randomness of it still leaves me scratching my head on what is causing the noise and why it's making it.

Thanks

 

[larkone]

You say you think it is not the logitech system but you haven't eliminated this yet. Try turning off everything except the speakers and test and then try connecting something like an MP3 player to them and test. Elimination testing is best done by starting at one end and working logically through the system, adding one component at a time.

Remove the UPS as part of this testing. Also try re-positioning the amp/cables and replace cables to eliminate those. Have you tried turning off the mike inputs to see if that stops it. Do you have on board sound - if yes then remove the Auzentech and try that. Not saying that your original concerns about the fan failing are not right but until you eliminate the obvious and easily tested then you could spend a lot of time chasing your tail.

 

[Uniformis]

Well I had removed the speakers and powered them off but there was still noise being captured by the sound card...

I tested connecting to the onboard sound and there was no noise coming from speakers, neither was the onboard mic source picking it up.

However the microphone source from the sound card was still picking it up.

Today I reconnected the speakers back to the sound card and disabled the microphone completely. There was no noise for a long time.

But even after I re-enabled the mic there has been none either. Even the mic source isn't picking up anything.

Yesterday I tested stopping a couple of fans while the noise was happening [Stopped at 11:50]. It seemed to stop when I stopped the CPU cooler fan. The fan is still working now, but there hasn't been any noise yet.

I also noticed a softer popping that was always present in the mic source recording (which I thought was normal at first, but then suspected it could be related to the louder noise) was also gone since I stopped the fan: http://soundcloud.com/asclepius123/now-and-before

From my fan sensors I also seem to remember seeing the CPU fan around 1360 RPM yesterday before I stopped it. It now sits around 1420 RPM.

Could it really have been the CPU fan after all?

 

[larkone]

Yes it could have been and at least they are cheap to replace. Glad you found it.

Soundcards inside PCs are always going to be an issue if you want high quality sound as they will always be subject to the huge amounts of noise and hash a PC kicks out.