
On some LCD monitors this will cause them to emit a tone (epilepsy warning) - 6581
http://thume.ca/screentunes/
======
gandalfu
From another thread here:
[https://news.ycombinator.com/item?id=8856829](https://news.ycombinator.com/item?id=8856829)

[https://news.ycombinator.com/item?id=8857209](https://news.ycombinator.com/item?id=8857209)

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.

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ddlatham
In some humans this page will cause the head to ache.

~~~
craftkiller
My refrigerator's compressor just happened to turn on when I clicked the link.
I was impressed.

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reconbot
Any thought that this might damage our monitors?

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bnegreve
Why is this downvoted, this is a very reasonable question.

Noise is a mechanical wave produced by something vibrating. If you can hear
it, it means that thing is vibrating quite hard inside your monitor.

~~~
hamiltonkibbe
The most likely culprit is inductor windings. The magnet wire used for
windings is generating a changing magnetic field which causes them to vibrate,
usually at the fundamental frequency of the excitation signal. (see image at
[http://www.digikey.com/product-
detail/en/744773122/732-1258-...](http://www.digikey.com/product-
detail/en/744773122/732-1258-2-ND/1638663) for an example.) This is a fairly
common source of audible noise in electronics.

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fauria
More info:
[https://news.ycombinator.com/item?id=8856829](https://news.ycombinator.com/item?id=8856829)

~~~
tmmm
eli5?

~~~
virmundi
[https://news.ycombinator.com/item?id=8857209](https://news.ycombinator.com/item?id=8857209)

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Cthulhu_
Interesting. My primary screen, a 27 inch Dell something-or-another costing me
€350+ a couple years ago gives an audible noise at the thinner bars.

My secondary screen though, a Fujitsu Siemens 19 inch thing probably eight
years old by now doesn't do a thing. However, that one broke down a couple of
years ago - the condensators in that one had broken, and my dad replaced them
with higher-voltage alternatives.

Note that monitors breaking down due to capacitor malfunction is a common
issue - the manufacturers intentionally install capacitors with a too low
voltage limit, which will cause the monitors to break down within 3-5 years,
shortly after the required 3 years warranty. Planned / designed obsolescence,
and stuff. Free business opportunity for anyone with a soldering iron: buy old
'broken' TFT screens and replace the broken capacitors with ones with higher
voltages.

(note I'm not an electronic engineer and I forgot all of my education about
the subject, my phrasing may be wrong)

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kefka
You're very right. Most electronics are from bad or undervolted caps.

The only thing to make sure is to put caps in the same polarity as the dead
one (assuming polarity of said caps; some dont).

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octo_t
Can we get a warning on the link for people susceptible to epilepsy, seizures
or migraines? Thanks.

~~~
skynetv2
also, no one knows if it can cause damage to hardware

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baldfat
If an image can cause damage to hardware we are in serious trouble with people
out for the LULZ

~~~
nitrogen
[https://news.ycombinator.com/item?id=8863041](https://news.ycombinator.com/item?id=8863041)

~~~
baldfat
LED noise is not due to something vibrating.

Former Sound Engineer and well LEDs make noise (super quiet). My guess it is
the transformer that is making the noise since a LED powered monitor is
regulating the voltage of the LED as needed if it didn't do that your power
use would be many times higher than with a voltage regulating transformer.

Wouldn't mean anything damaging is happening at all.

~~~
nitrogen
_LED noise is not due to something vibrating._

The definition of noise is, literally, something vibrating.

~~~
baldfat
The definition of light is also vibrating aka waves :)

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slashnull
I'm not crazy!

Some text patterns (like, say, grep going through minified JS) make my monitor
emit a weird noise I was having all the trouble in the world believing.

Now I know this tone _actually exists_

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wyager
As I was holding my iPhone up to my ear, I realized that there is a constant
static noise coming out of my phone speaker, even with the volume down!

This page also produces a tiny bit of inductor noise near the middle of the
device.

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freshyill
Nothing on my Retina MacBook Pro, Thunderbolt Display or 2011 27" iMac. Then
again, I've got pretty bad ears. Now I need to send this to coworkers to see
if their mileage varies.

~~~
jlmorton
I have a 2011 27" iMac and I can hear it, but it's on the edge of my
perception.

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scoopr
I thought listening to CRT with AM radio was cooler, with Tempest for Eliza[0]
:)

[0] [http://www.erikyyy.de/tempest/](http://www.erikyyy.de/tempest/)

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nikbackm
I've noticed this phenomenon before, then with the V File Viewer in CSV table
mode until I changed its default colors.

This page did not seem to trigger it though.

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tzs
I'm somewhat relieved by this. I thought I had something wrong with one of my
monitors. If I open a terminal window, make it cover most of the screen, and
then view something with lots of long lines (such as Apache logs), I get a
whining tone. It's bugged me for a long time not knowing what could be causing
it.

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Rooster61
It would be fun to set this to a musical score, and run it on three monitors
in harmony.

Also, for some reason the effect reminds me of this video:
[https://www.youtube.com/watch?v=Ht96HJ01SE4](https://www.youtube.com/watch?v=Ht96HJ01SE4)

~~~
ugexe
I was hoping it was going to be musical and not just a rehash of the post from
yesterday :(

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ljd
It sounds like a circular saw. I guess certain sinusoidal patterns sound the
same.

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teh_klev
I have two Dell 2408WFP panels which didn't exhibit this behaviour. The older
2405 panel did (and the pitch changed as the bars narrowed and widened),
although it was barely audible.

~~~
iolothebard
You should try tinnitus, nothing is barely audible ;-)

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taternuts
Wish I could get it to work to check it out. I've tried with my 4k monitor, an
HP laptop, and a macbook air, and just in case a galaxy S5 and I'm not getting
anything.

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JohnBooty
Works on a Dell U2713HM. The noise (well... at least the portion of the noise
I'm capable of hearing) occurs when the bars are at their fattest. It's barely
audible.

~~~
stronglikedan
My LG W2242P does it for a range where the bars are at there thinnest. When
they start getting close to thinnest, it gets higher pitched, and then
reverses when they start to thicken again.

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Fuxy
Confirmed with LG 22MP65 IPS LED and iiyama ProLite E1906S.

You can hear a faint sound when the lines reach a certain distance from each
other and it fades out as the distance changes.

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codeaken
Way cool, worked on my Dell U3011! How does this function, why does the screen
emit a high pitched noise?

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paulmd
There's a working theory in the Github explanation.

White and black pixels take different amounts of power to draw. As the screen
scans up and down to draw the various rows, it thus has to rapidly charge and
discharge the capacitors. The capacitors are expanding and contracting a bit
as they do so, which vibrates the air and makes a tone.

Frankly this sounds like an awesome way to blow up those capacitors.

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colinbartlett
27" iMac does indeed emit a tone.

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jws
Late 2009, 27" iMac: emits tone.

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dmschulman
I noticed this same effect with the Scroll Slow, Have Fun
(scrollslowhavefun.com) demo from yesterday.

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shmerl
Can it damage those monitors?

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Zardoz84
My old Samsung's SyncMaster T200 sound a little at the thinner bars.

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mariuolo
It does on mine (24" eIPS) at like 30% reduction.

Any chance of damage?

~~~
Cthulhu_
TBH if your monitor would break due to a video signal I'd get a refund for
supplying a sub-par product. Video signals shouldn't be able to break hardware
(just people's brains according to some of the comments)

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paulmd
Dell P2210 emits a tone. Motorola Moto G phone does not.

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gojomo
Can it be made to play 'Ode to Joy'?

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goetterfunke
Confirmed iiyama PL2779Q. Loud and clear

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dumbfounder
I think the tone is my eyes screaming.

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landtco
This is some black mirrorish stuff here... I've suddenly forgotten who I am.

~~~
angersock
Long live the new flesh!

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VMG
works here!

but could use a warning

~~~
smacktoward
I would think "on some LCD monitors this page will cause the screen to emit a
tone" would count as a warning? :-D

