intermittent buzzing

tOsYZYny

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I started having intermittent buzzing through my headphones, either connected through the stereo out jack or the USB ones. It seems to last for a few seconds before going away to return a little while later.

I thought at first it was the USB headphones going bad as that is when I first noticed it, but then I also noticed it with my audio / 3.5mm stereo jack headphones plugged directly into the computer. Muting the sound fixes the issue, so it seems like a software and not a hardware problem. I have this problem with pianobar, google voice calls in chromium, etc. It also consistently effects the right-channel only for both the analog and USB headphones.
 

Mjölnir

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But when it's only on the right audio channel, I would guess it's the audio hardware. There must be some DAC & an analog amplifier. I can imagine that the latter wears out after some time. Is that an old machine?
 
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tOsYZYny

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I would agree but it is odd that muting it kills the buzzing. Depends on what you mean by "old", it is a 3rd generation i7, so around 2013-era? It isn't new, but it isn't ancient either. Hmm, I was thinking about piping the audio out a different audio card, but I already did that when piped it out through the USB headset. The problem was still there, so I'd bet that if I also try the Nvidia video card, I'd have the issue there too.
 

shkhln

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The problem was still there, so I'd bet that if I also try the Nvidia video card, I'd have the issue there too.
Try it. USB headphones are powered by a computer PSU, while monitor obviously isn't.
 

drhowarddrfine

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it seems like a software and not a hardware problem. I have this problem with pianobar, google voice calls in chromium, etc. It also consistently effects the right-channel only for both the analog and USB headphones.
Then it's a hardware problem, not a software one.
 
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tOsYZYny

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I am trying that now - so, if I don't hear any buzzing, then you're thinking it could be the PSU? I haven't noticed it yet.
 

obsigna

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Turn your cell phone off. I assume, it is not sitting on your e-guitar, otherwise the buzzing would not be intermittent:-D

View: https://www.youtube.com/watch?v=XTiatPUKTrM
Anyway, cell phones produce intermittent buzzing in audio devices. Most famous is the GSM sound, however this might happen with G3 as well. I sometimes hear this in the sound system of my car when I stow the iPhone near the sound amplifier.
 

drhowarddrfine

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Muting it kills the amplifier which is what feeds your speakers or earphones. Wiggle the earphones at the connector to the computer just for grins to see if anything changes. Take a pencil with an eraser or a wooden stick or dowel and tap, in some multitude of places, on your board, motherboard, connectors, power supply ,etc. inside your box and see if you hear anything change. Wiggle wires in there, too.
 
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tOsYZYny

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That sounds like it could be something from Pink Floyd ...

The sound seemingly works fine going through the monitor. I'll fiddle around with the other settings...
 

mark_j

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I started having intermittent buzzing through my headphones, either connected through the stereo out jack or the USB ones. It seems to last for a few seconds before going away to return a little while later.

I thought at first it was the USB headphones going bad as that is when I first noticed it, but then I also noticed it with my audio / 3.5mm stereo jack headphones plugged directly into the computer. Muting the sound fixes the issue, so it seems like a software and not a hardware problem. I have this problem with pianobar, google voice calls in chromium, etc. It also consistently effects the right-channel only for both the analog and USB headphones.
It sounds like RFI. If it was me, I would wind the cable of the headphones over an RF choke and see if it removed or abated the sound. If it does, bingo.
It's most likely a power source issue, either from mains or your computer. I've seen fans also exhibit this issue.
If you have an AC Filter now would be a good time to use it. Something like this. (Though they're by no means foolproof and I'm not endorsing this particular unit).
 
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tOsYZYny

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All of my computers are on battery backup. This particular one is on one that should smooth out power as well. So, the power should be "clean".
 

Mjölnir

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All of my computers are on battery backup. This particular one is on one that should smooth out power as well. So, the power should be "clean".
But the PSU (it's capacitors) can wear out. And/or the VR unit (in the PSU, on main board, on-chip), IIRC these do have capacitors, too. Concerning electronic parts -- IIRC -- in general, capacitors belong to the parts that wear out the fastest. Another issue: some nerds think it's cool to have an open housing - given the story above with interference from radio waves, that's not a good idea. Since it's only one channel, I'm 98% shure it's a hardware issue. If that box ran often for 7 years, maybe sometimes with insufficient cooling, you might see the 1st signs of dieing hw.
 
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tOsYZYny

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I'm now getting the buzzing through the monitor too :(.

It's not 60Hz, 60Hz would be pleasant to the ear compared to this. It is a bit higher. I'm too slow to capture it with my audio recorder, but I don't know if you guys are from the US, but the sound reminds me of the hearing tests we had in elementary school where they'd play a buzzing tone at various frequencies. The tone is upper middle if that helps, it's certainly much higher than 60Hz, but definitely nowhere near 20kHz. I listened to some random tones on youtube, and I'd guess it is somewhere around 2kHz. But, the problem is that it isn't a nice clean sine wave, maybe that is why it hurts the ears so much...
 

Mjölnir

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If you have more than one boxes, you could take the PSU of one of these, if it matches. Not only the connectors, the design power, too. Sorry, for shure you know that.
 
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tOsYZYny

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Thanks - yes, my limitation will be the power. I have other PSUs, but they're rated a bit lower and with the graphics card I have in here, I'm already at the minimum. Time for a new box :)! I will try downgrading the PSU and temporarily using the onboard video ...
 

Snurg

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There is no mention which kind of audio cables are being used.

A few years ago I had a similar problem, and it resulted in throwing away almost all of my audio cables.

The reason is that with the cheap cables usually delivered with PC or (low cost) sound card hardware are no longer "shielded" in the sense I was accustomed to.
When I finally boiled down to physically destructively examine the cables, I found out that the core, consisting of a barely visible thin wire, was not surrounded with a wire mesh, instead there was only another thin wire, no mesh at all.

Shocked, I opened more and more cables, only to find out that of these characteristic black audio cables with the plastic plugs molded on, maybe one of five actually was shielded. But even these were not shielded well, particularly the plugs were not covered at all, inviting all kinds of RFI.

In disgust I purchased a handful of quality plugs (metallic, shielded) and a few meters of quality cable with thicker wires and good mesh insulation, just to make the few cables I need myself in professionally accepable quality.
 
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tOsYZYny

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Hmm, good food for thought. I will try the PSU first. I can tolerate running on the system's onboard video for a bit ...
 

Snurg

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Well, 2kHz is not common with PSUs. These usually work in the range 100-140kHz.
And the capacitor problems mentioned here result in ripple/spikes in this frequency range.
But it is always good to watch out for bulgy caps.

Regarding the "battery backup", I would be very wary of that.
Most of the temporary UPS have a stairwave waveform, which would correlate with the frequency you describe.
This is an extremely dirty way to feed PSUs, causing thousands instead of only 50/60 surges/sec that seep through to the PSU output.
Maybe you hear the noise just when laptop switches from battery to PSU to recharge...?
 

olli@

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Wait … This appears both when using the 3.5mm analog jack, and when using USB audio output? And it’s only on the right channel, not on the left?
Then it cannot be the hardware. It must be a software issue, I’m afraid.

How can a defective power supply cause a buzzing sound only on the right channel of a digital audio stream sent through an USB port? I really cannot imagine how that could be possible.
 

Snurg

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Wait … This appears both when using the 3.5mm analog jack, and when using USB audio output? And it’s only on the right channel, not on the left?
Then it cannot be the hardware. It must be a software issue, I’m afraid.

How can a defective power supply cause a buzzing sound only on the right channel of a digital audio stream sent through an USB port? I really cannot imagine how that could be possible.
The description of the configuration is not 100% clear to me. If it is actually digital audio (for which the 3.5mm stereo connector is not really common), then it is definitely an issue in the analog part of the audio chipset, be it caused by hardware or software. Clipping would have to be ruled out, too.

It could even be possible that only the first channel gets completely initialized and some bad NID wirings on the others have been left active, and this being noticed only much later because of increasing noise due power quality decrease over time.

If the OP could show how the signal looks on an oscilloscope, that would be nice.
 
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tOsYZYny

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Well, I couldn't easily swap PSUs, so I moved the hard drives over to an older machine ... There is no buzzing there, yet ...

I don't have an oscilloscope. If it were software, wouldn't I expect to hear the buzzing already?
 

olli@

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Well, I couldn't easily swap PSUs, so I moved the hard drives over to an older machine ... There is no buzzing there, yet ...

I don't have an oscilloscope. If it were software, wouldn't I expect to hear the buzzing already?
Does that older machine have a different audio chip? (The mainboard’s manual should mention what kind of audio chip it has.)
I suspect it’s a bug in FreeBSDs driver for the audio chip of the 1st machine.
Uhm, wait, it can’t be the driver, because then it wouldn’t affect the USB headphones (those use a different driver, namely snd_uaudio(4)).

It could be a problem with the snd(4) kernel framework, or with a userland framework (e.g. Alsa, Pulseaudio, whatever). But in that case the problem should persist when you move the hard drive to a different machine. Also, other people should have similar problems, but this is the first time I hear something like that.

Do you have any special sound-related settings in /boot/loader.conf, /etc/sysctl.conf or elsewhere?

Anyway – As I said before, if the buzzing sound is clearly only on the right channel, then it’s certainly not the power supply causing this.

PS: How often does that buzzing appear? Every minute, once per hour, …?
 
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tOsYZYny

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It was working fine with no issues for the past year. I recently discovered that I had a bug in my system update logic that caused a few issues, but I think I sorted that out by doing freebsd-update and stopping pkg update and pkg upgrade.

The old box I am on now is using:
NM10/ICH7 Family High Definition Audio Controller
and the video card's audio chip is GP107GL High Definition Audio Controller (which I also moved over to the old box).

I haven't put the new box back together, but will do that this afternoon.
 
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