Whine when playing video
#1
Noticing that the PBP emits a whine whenever video is playing.

The whine disappears shortly after the video is paused or stopped.

Anyone else noticing the same?
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#2
I was noticing a bit of a whine when I was first messing with it, whenever a GPU operation took place. I can't seem to get it to happen again now, because I think I sneezed in the wrong place and made GPU acceleration stop working (thanks, silicon vendors!). In any case, this particular phenomenon is one I'm familiar with: GPUs, for whatever reason, pull a lot of power in sharp pulses. This tends to cause switched-mode power supplies to respond by ramping up their output in pulses in kind, which produces all kinds of mad EMI that sprays everywhere. On my phone, for example, I can hear little buzzy noises whenever the UI moves around while I'm listening to music in wired earbuds - and much more startlingly, I can hear these same noises coming from the wallwart power supply whenever I use it in a quiet room while it's plugged in! The fact that the power fluctuations make it that far out of the phone without being buffered away is rather concerning...

My guess is that the whine you're describing is caused by this GPU-related power flutter. If it's loud enough to be a problem, there are a few things you might try to fix it, but since it's a hardware issue, none of them are particularly easy or ideal. If it's only happening with the speakers on (were you playing sound through them from the video?), then it might just be a matter of turning the onboard speakers off and using a bluetooth speaker instead, which will avoid having the audio system amplify the whine and spew it into the audio. If it's actually coil whine coming out of the power regulator itself, and not from the speakers, then that's another matter, though in earnest I can't quite believe that any laptop power regulator could generate a whine loud enough to be a serious problem without also being at death's door, one way or another.

With luck, using a wireless speaker with its own power supply will do the trick. If not, we guess the thing to do would be to open it up, find the power rail that's most directly involved in feeding the GPU, and solder a great big buffering capacitor to it. But that sounds pretty tricky and risky.
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#3
I noticed the whining happened when it tried to play any sound, it stopped a couple of seconds after the sound had finished playing. So, no, it's not related to video playback. Also, it happened both to the internal speakers and headphones. It's probably just a bad circuitry. I guess, we just have to live with it.
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#4
(11-07-2019, 07:14 PM)diodelass Wrote: I was noticing a bit of a whine when I was first messing with it, whenever a GPU operation took place. I can't seem to get it to happen again now, because I think I sneezed in the wrong place and made GPU acceleration stop working (thanks, silicon vendors!). In any case, this particular phenomenon is one I'm familiar with: GPUs, for whatever reason, pull a lot of power in sharp pulses. This tends to cause switched-mode power supplies to respond by ramping up their output in pulses in kind, which produces all kinds of mad EMI that sprays everywhere. On my phone, for example, I can hear little buzzy noises whenever the UI moves around while I'm listening to music in wired earbuds - and much more startlingly, I can hear these same noises coming from the wallwart power supply whenever I use it in a quiet room while it's plugged in! The fact that the power fluctuations make it that far out of the phone without being buffered away is rather concerning...

My guess is that the whine you're describing is caused by this GPU-related power flutter. If it's loud enough to be a problem, there are a few things you might try to fix it, but since it's a hardware issue, none of them are particularly easy or ideal. If it's only happening with the speakers on (were you playing sound through them from the video?), then it might just be a matter of turning the onboard speakers off and using a bluetooth speaker instead, which will avoid having the audio system amplify the whine and spew it into the audio. If it's actually coil whine coming out of the power regulator itself, and not from the speakers, then that's another matter, though in earnest I can't quite believe that any laptop power regulator could generate a whine loud enough to be a serious problem without also being at death's door, one way or another.

With luck, using a wireless speaker with its own power supply will do the trick. If not, we guess the thing to do would be to open it up, find the power rail that's most directly involved in feeding the GPU, and solder a great big buffering capacitor to it. But that sounds pretty tricky and risky.

Thanks @diodelass - I've heard of GPU coil whine before and was hoping it wasn't the cause. Will try to pinpoint the culprit component emitting the whine.
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#5
I have a quiet environment and a good microphone available, so I think I'll spend some time today recording what my unit sounds like under various conditions, just so we can get some references there.

-- EDIT:
This may not actually be useful, because I can't get my unit to produce any extraneous noise related to video playback. I've got a video playing in Chromium on Youtube in full-screen 1080p60 - which I understand would not be possible without hardware acceleration - and the sound from the speakers with silent audio playing (so the speakers are active, but being given a flat signal that should produce no sound) is only at the very edge of audible.
I can get the power regulator to emit a very audible coil whine by plugging in a USB-to-barrel-plug cable connected at the other end to a 2.0A power supply, but I suspect this would be a pretty obvious culprit and is also likely not very good for the unit.
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#6
I've notice the whine on mine as well. With sound on mute and playing a video from youtube in chromium and also playing an mkv with mpv, the sound is discernible. But it does seem to be directly link to some part of the gpu, because I have been unable to create the whining noise using stress-ng to perform a load test. It isnt terrible, and with the sound unmuted or head phones in the noise isnt noticeable, so not a major issue, but if anyone has any possible fixes id be interested.
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#7
It is the same on mine. The whine is also there with the sound muted. The symptoms are exactly he same as yours.
Other than this the laptop very well on Ubuntu Smile
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#8
I confirm the whimpering sound.

Guys, this has nothing to do with CPU / GPU being under load. Run the famous gears simulation if in doubt. Or, playback audio without any video simply with a command line player.

I understand this is purely a sound issue. Whenever the software brings the sound system up for playback you can hear this noise. When the playback stops, the sound interface is turned off after 5sec or so to save energy (I guess).

My main concern is that this might be an actual hardware issue, if say the filters aren't designed right and voltage fluctuations speak over to the D/A converter. I hope some of the hardware developers will comment on this issue.

On thing is for sure: this is a REAL pain. Unless you are working in terribly loud environments this sound is really disturbing and makes listening to music particularly annoying since you have this constant whining sound also in quiet parts of songs.

EDIT: those concerned with whether your output is muted or not. Muting the sound means the volume (in the driver) is reduced to 0. This does not change the fact that the actual sound interface (D/A converters and such) are still powered up (which seems to produce the whining sound).
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#9
(11-09-2019, 06:35 AM)Firestorm Wrote: I confirm the whimpering sound.

Guys, this has nothing to do with CPU / GPU being under load. Run the famous gears simulation if in doubt. Or, playback audio without any video simply with a command line player.

I understand this is purely a sound issue. Whenever the software brings the sound system up for playback you can hear this noise. When the playback stops, the sound interface is turned off after 5sec or so to save energy (I guess).

My main concern is that this might be an actual hardware issue, if say the filters aren't designed right and voltage fluctuations speak over to the D/A converter. I hope some of the hardware developers will comment on this issue.

On thing is for sure: this is a REAL pain. Unless you are working in terribly loud environments this sound is really disturbing and makes listening to music particularly annoying since you have this constant whining sound also in quiet parts of songs.

EDIT: those concerned with whether your output is muted or not. Muting the sound means the volume (in the driver) is reduced to 0. This does not change the fact that the actual sound interface (D/A converters and such) are still powered up (which seems to produce the whining sound).

I believe you are correct with your diagnosis about it being a sound system issue. I can absolutely produce the noise while playing an mp3 file from the command line with mplayer, and pulseaudio muted.
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#10
If you set the brightness of the screen to the maximum, the noise disappear. This means that it is the PWM used to set the brightness of the screen which is causing this.
We will have to see if it is possible to add some shield around the components which are setting the brightness.
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