7 ms·

This somehow manages my monitor to make a high pitched sound. It's an LCD monitor. It's the actual monitor making the sound. Switching to a different window or

This somehow manages my monitor to make a high pitched sound. It's an LCD monitor. It's the actual monitor making the sound. Switching to a different window or tab makes the sound top. Taking a screenshot of the tab, and closing the tab but viewing the screenshot, produces the sound.

aw3c2 12y ago
Same here, I first thought it was the gfx card's capacitors. They usually like doing that when I use things with pixel shaders (obviously a different thing but it reminded me).
- deleted 12y ago
  [deleted]
- _sigma 12y ago
  Furmark always does it to my cards. Perhaps of interest. http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/67822-graphics-card-coil-whine-investigation.html http://www.hardwarecanucks.com/forum/hardware-canucks-review...
fauria 12y ago
Same here on a MBP.
- danielweber 12y ago
  I've got a MacBook Pro, but slightly older, and I'm not hearing it. Mine still has the ghosting issue, which makes me wonder if that issue is stopping this issue.
- lukashed 12y ago
  Mine doesn't (Retina without ghosting). Though, when scrolling on the site, _something_ (it's not the screen) is making weird noises, almost like the sound when accessing a HDD. I have an SSD though. I had the same issues with other sites / applications when scrolling in general as well. Even more noticeable with the MacBook Air I had before. Is there any rational explanation for this?
  - chc 12y ago
    I used to have a computer that did that a long while back. It made a whistle whenever I'd scroll. IIRC I decided it was the video card, though I'm not sure I ever confirmed it.
  - userbinator 12y ago
    The first thing to know is that the power consumption of modern CPUs varies hugely between idle and full-speed; from a few watts to several dozen. When you are just looking at the screen, and the machine is otherwise idle, the CPU is not doing much, so it goes into low-power low-frequency mode and "sleeps" until some event occurs. When you put fingers on the trackpad and scroll, it sends an "interrupt" to the CPU, telling it that a scroll event has occurred; in a few microseconds the CPU goes from idle to full power to process that scroll event, then goes back to sleep again. The GPU might also be involved in the same way. Every little scroll movement results in an interrupt, so when you are scrolling at a constant rate interrupts occur at a fixed frequency, and the system is going from idle to full power many times a second. The pulses of power draw that this creates, happening at audible frequencies, causes various components like inductors and capacitors to emit sound.
tlrobinson 12y ago
This is way more fascinating than the site itself...
alextgordon 12y ago
Damn you for making me look like a fool with my ear up against the screen. (No sound here)
dfragnito 12y ago
May be your age. Higher pitched frequencies are often heard by you youngsters but not us old folk.
knd775 12y ago
Mine too. What is this sorcery?
poopchute 12y ago
My monitor also makes a high pitched noise. Sony KDL-32EX400 (using HDMI connection). Neither of my other monitors produce the noise (VGA, & Displayport connections if it matters)
pandringa 12y ago
Same sound here - only on my external monitor though, not on my MBP's own screen.
drivers99 12y ago
"Some surface-mount capacitors exhibit acoustic noise when operated at frequencies in the audio range." [1] I see that this screen has alternating black and white lines. I count 43 black lines on my monitor. Assuming 60 Hz refresh rate, that is 2580 Hz in terms of the pixels being off or on, which is a perfectly audible frequency. Even with 120 Hz refresh rate, that would be 5160 which is still easily audible. Without knowing anything else, I guess that there may be a capacitor somewhere that is charging and discharging along with the brightness of the screen as it is refreshed from top to bottom, which is causing it to flex in a way that produces an audible noise. I am curious is Aardwolf can produce different frequencies by varying the width (and therefore the quantity) of black and white lines on the screen. If so, you should be able to play some music on it. [1] http://www.edn.com/design/components-and-packaging/4364020/Reduce-acoustic-noise-from-capacitors http://www.edn.com/design/components-and-packaging/4364020/R...
- lultimouomo 12y ago
  Something quite different, but it reminds me of Tempest for eliza: http://www.erikyyy.de/tempest/ http://www.erikyyy.de/tempest/ That was a cool hack!!
- ashmud 12y ago
  Zooming in and out does produce different audible frequencies on my screen.
- userbinator 12y ago
  If so, you should be able to play some music on it. Also makes for a nice covert channel... similar tricks with "listening" to the noises a computer makes have been shown to be possible to use for extracting information like encryption keys: https://news.ycombinator.com/item?id=6927905 https://news.ycombinator.com/item?id=6927905
- hamiltonkibbe 12y ago
  Inductors do this as well. The changing magnetic field causes the windings to vibrate, creating an audible sound. The sound my work monitor makes sounds like an inductor to me.
thepumpkin1979 12y ago
Does this work for for anybody on MBP or Retina displays? I tried mouse-wheel, trackpad and scroll bar, can't hear anything. anybody?
- michaelchum 12y ago
  Nothing for me either with a rMBP
JackuB 12y ago
Can confirm same high pitched sound on 27 iMac. Plus: open developer toolbars, find styles for .bars, change margin-bottom and sound changes frequency.
userbinator 12y ago
It doesn't happen to mine but I can see how it could - the liquid crystal is driven with a high-frequency signal whose voltage basically corresponds to the intensity of the pixel, and when images containing repetitive content are displayed, that signal will follow the content of the image; the current that drives the display also follows that signal, and if the signal contains frequencies that happen to excite resonances in the audible range in some components of the hardware, you can hear it. http://en.wikipedia.org/wiki/Coil_noise http://en.wikipedia.org/wiki/Coil_noise http://www.ukgamingcomputers.co.uk/capacitor-squeal-coil-whine-explained-a-63.html http://www.ukgamingcomputers.co.uk/capacitor-squeal-coil-whi... http://electronics.stackexchange.com/questions/34806/what-might-be-the-cause-of-high-pitch-sound-coming-from-a-switching-regulator-ci http://electronics.stackexchange.com/questions/34806/what-mi...
phaker 12y ago
It's because of these horizontal bars, you can get the same effect with similar graphics: All video interfaces we use transmit data serially, line by line, pixel by pixel. The bars are 16px tall (black + white) so at 60Hz and 1920×1080px they'll produce a tone with fundamental frequency of 4.05kHz (60Hz × 1080 lines / 16 lines) and harmonics.
ashmud 12y ago
Same on my work LCD. Dell E207WFP. I also tried test patterns at http://www.lagom.nl/lcd-test/ http://www.lagom.nl/lcd-test/ and http://www.testufo.com/ http://www.testufo.com/. None of those made caused my screen to make an audible sound.
tricolon 12y ago
Same here on my Monoprice 27" IPS LED monitor: http://www.monoprice.com/Product?p_id=10489 http://www.monoprice.com/Product?p_id=10489
HCIdivision17 12y ago
I'll confirm a tone shift on an HP ZR2740w as well. It's quiet, and I have to put my ear to the back of the monitor to notice as I alt-tab the window. But it's certainly there. (I'm trying to get a recording, but I work in a plant and it's a bit full of white-ish noise...)
monochromatic 12y ago
I have two identical monitors. One of them makes a high pitched sound on this page, and the other is perfectly fine. Weird.
deleted 12y ago
[deleted]
frik 12y ago
I recently tested my new TFT (TN-panel) monitor with a monitor test application, and noticed an high pitched sound on a very specific blue line pattern too. I turned down the brightness from 100% to 80% and that reduced it.

aw3c2 12y ago

Same here, I first thought it was the gfx card's capacitors. They usually like doing that when I use things with pixel shaders (obviously a different thing but it reminded me).

deleted 12y ago
[deleted]
_sigma 12y ago
Furmark always does it to my cards. Perhaps of interest. http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/67822-graphics-card-coil-whine-investigation.html http://www.hardwarecanucks.com/forum/hardware-canucks-review...

fauria 12y ago

Same here on a MBP.

danielweber 12y ago
I've got a MacBook Pro, but slightly older, and I'm not hearing it. Mine still has the ghosting issue, which makes me wonder if that issue is stopping this issue.
lukashed 12y ago
Mine doesn't (Retina without ghosting). Though, when scrolling on the site, _something_ (it's not the screen) is making weird noises, almost like the sound when accessing a HDD. I have an SSD though. I had the same issues with other sites / applications when scrolling in general as well. Even more noticeable with the MacBook Air I had before. Is there any rational explanation for this?
- chc 12y ago
  I used to have a computer that did that a long while back. It made a whistle whenever I'd scroll. IIRC I decided it was the video card, though I'm not sure I ever confirmed it.
- userbinator 12y ago
  The first thing to know is that the power consumption of modern CPUs varies hugely between idle and full-speed; from a few watts to several dozen. When you are just looking at the screen, and the machine is otherwise idle, the CPU is not doing much, so it goes into low-power low-frequency mode and "sleeps" until some event occurs. When you put fingers on the trackpad and scroll, it sends an "interrupt" to the CPU, telling it that a scroll event has occurred; in a few microseconds the CPU goes from idle to full power to process that scroll event, then goes back to sleep again. The GPU might also be involved in the same way. Every little scroll movement results in an interrupt, so when you are scrolling at a constant rate interrupts occur at a fixed frequency, and the system is going from idle to full power many times a second. The pulses of power draw that this creates, happening at audible frequencies, causes various components like inductors and capacitors to emit sound.

tlrobinson 12y ago

This is way more fascinating than the site itself...

alextgordon 12y ago

Damn you for making me look like a fool with my ear up against the screen. (No sound here)

dfragnito 12y ago

May be your age. Higher pitched frequencies are often heard by you youngsters but not us old folk.

knd775 12y ago

Mine too. What is this sorcery?

poopchute 12y ago

My monitor also makes a high pitched noise. Sony KDL-32EX400 (using HDMI connection). Neither of my other monitors produce the noise (VGA, & Displayport connections if it matters)

pandringa 12y ago

Same sound here - only on my external monitor though, not on my MBP's own screen.

drivers99 12y ago

"Some surface-mount capacitors exhibit acoustic noise when operated at frequencies in the audio range." [1] I see that this screen has alternating black and white lines. I count 43 black lines on my monitor. Assuming 60 Hz refresh rate, that is 2580 Hz in terms of the pixels being off or on, which is a perfectly audible frequency. Even with 120 Hz refresh rate, that would be 5160 which is still easily audible. Without knowing anything else, I guess that there may be a capacitor somewhere that is charging and discharging along with the brightness of the screen as it is refreshed from top to bottom, which is causing it to flex in a way that produces an audible noise. I am curious is Aardwolf can produce different frequencies by varying the width (and therefore the quantity) of black and white lines on the screen. If so, you should be able to play some music on it. [1] http://www.edn.com/design/components-and-packaging/4364020/Reduce-acoustic-noise-from-capacitors http://www.edn.com/design/components-and-packaging/4364020/R...

lultimouomo 12y ago
Something quite different, but it reminds me of Tempest for eliza: http://www.erikyyy.de/tempest/ http://www.erikyyy.de/tempest/ That was a cool hack!!
ashmud 12y ago
Zooming in and out does produce different audible frequencies on my screen.
userbinator 12y ago
If so, you should be able to play some music on it. Also makes for a nice covert channel... similar tricks with "listening" to the noises a computer makes have been shown to be possible to use for extracting information like encryption keys: https://news.ycombinator.com/item?id=6927905 https://news.ycombinator.com/item?id=6927905
hamiltonkibbe 12y ago
Inductors do this as well. The changing magnetic field causes the windings to vibrate, creating an audible sound. The sound my work monitor makes sounds like an inductor to me.

thepumpkin1979 12y ago

Does this work for for anybody on MBP or Retina displays? I tried mouse-wheel, trackpad and scroll bar, can't hear anything. anybody?

michaelchum 12y ago
Nothing for me either with a rMBP

JackuB 12y ago

Can confirm same high pitched sound on 27 iMac. Plus: open developer toolbars, find styles for .bars, change margin-bottom and sound changes frequency.

userbinator 12y ago

It doesn't happen to mine but I can see how it could - the liquid crystal is driven with a high-frequency signal whose voltage basically corresponds to the intensity of the pixel, and when images containing repetitive content are displayed, that signal will follow the content of the image; the current that drives the display also follows that signal, and if the signal contains frequencies that happen to excite resonances in the audible range in some components of the hardware, you can hear it. http://en.wikipedia.org/wiki/Coil_noise http://en.wikipedia.org/wiki/Coil_noise http://www.ukgamingcomputers.co.uk/capacitor-squeal-coil-whine-explained-a-63.html http://www.ukgamingcomputers.co.uk/capacitor-squeal-coil-whi... http://electronics.stackexchange.com/questions/34806/what-might-be-the-cause-of-high-pitch-sound-coming-from-a-switching-regulator-ci http://electronics.stackexchange.com/questions/34806/what-mi...

phaker 12y ago

It's because of these horizontal bars, you can get the same effect with similar graphics: All video interfaces we use transmit data serially, line by line, pixel by pixel. The bars are 16px tall (black + white) so at 60Hz and 1920×1080px they'll produce a tone with fundamental frequency of 4.05kHz (60Hz × 1080 lines / 16 lines) and harmonics.

ashmud 12y ago

Same on my work LCD. Dell E207WFP. I also tried test patterns at http://www.lagom.nl/lcd-test/ http://www.lagom.nl/lcd-test/ and http://www.testufo.com/ http://www.testufo.com/. None of those made caused my screen to make an audible sound.

tricolon 12y ago

Same here on my Monoprice 27" IPS LED monitor: http://www.monoprice.com/Product?p_id=10489 http://www.monoprice.com/Product?p_id=10489

HCIdivision17 12y ago

I'll confirm a tone shift on an HP ZR2740w as well. It's quiet, and I have to put my ear to the back of the monitor to notice as I alt-tab the window. But it's certainly there. (I'm trying to get a recording, but I work in a plant and it's a bit full of white-ish noise...)

monochromatic 12y ago

I have two identical monitors. One of them makes a high pitched sound on this page, and the other is perfectly fine. Weird.

deleted 12y ago

[deleted]

frik 12y ago

I recently tested my new TFT (TN-panel) monitor with a monitor test application, and noticed an high pitched sound on a very specific blue line pattern too. I turned down the brightness from 100% to 80% and that reduced it.