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.
"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.
I also put some ideas on the Github Readme including using feedback from the microphone to calibrate a width->pitch mapping to play music using your screen.
You shouldn't even need the microphone. Assuming that doubling the line frequency doubles the audio frequency, you can play music by just choosing a note to call "A" and varying the frequency from there. It won't be in tune, but that doesn't really matter.
I can hear the result of this, but it's barely audible, and only near the top of the range, at bar widths thinner than the OP.
I'll have to find some other monitors to test this on. It would be awesome if there were some commplace model that's relatively loud for a wide pitch range. Said model might then be useful for musical hacks in the same vein as driving the stepper motors in old floppy drives.
Hey! For me, this produces sound for the whole range of heights/frequencies! It plays a bit more silent for high frequencies, but for the lowest ones, the sound is quite loud (given it's produced by a screen...) and I think, it could easily go for an even lower pitch.
I am using a modified SyncMaster 203B (I replaced some of the electrolytic capacitors after the lighting ceased to work, so that may be it...)
Neat. I don't notice anything/much for most of the cycle, but somewhere in the middle I can hear a brief "zwip" rising tone, for part of a second. I happen to have three "identical" monitors, and it's similar on each one, although I believe I can hear the tone for a somewhat longer range on one of them.
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:
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.
You'll find it a lot in switching DC-DC converters as well. The pass inductors that help filter out the switching frequency can make quite a bit of noise, especially at higher loads.
My dimmable touch lamp makes an annoying high-pitched sound that is loudest on the dimmest mode. I searched for an explanation and apparently some light bulbs have filaments that are flimsy or light-weight enough that they vibrate audibly.
The power supply on the old Apple II "chirped" when switched off. I always understood it to be the oscillator decaying down from 20 KHz to DC in half a second or so.
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.
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.
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...)
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)
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).
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?
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.
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.
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.
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.
Will be released in the next 4 weeks. It was fun to make, but also quite nightmarish in the technical details. It is a hell of work (we have roughly 30 animations in the book, very small and very big ones). It requires extremely accurate measurements for the grid-foil and a sophisticated workflow and color management.
In the first run, the printer forgot to fixate the ink on the grid-foils with a protective layer, so using the foil would smear the black color.
I had this as well and was fascinated by it as a youngster. Seeing this site today brought those memories to the surface in a rush of nostalgia. This link in the comments was icing on the cake, thanks!
Isn't this how those "3D" panels work as well? It's the same thing printed, but with a plastic prism-esque thing on top showing different views from different angles.
Most 3D panels use an array of lenticular lenses to convert incident angle to position[1].
Note that the 3DS actually uses a parallax barrier, which is similar to this, but with the stripes far enough out-of-plane to the image to allow each eye to see a different part of the image[2].
The book my daughter has works just like this website, with black stripes on a transparent layer, and a layer immediatly below that is attached to the spine, but not the outer layer, causing it to move relative to the stripes as the page is turned[3].
The book has been printed and is currently delivered to stores and Amazon. The Amazon-link above will come up with previews in the next couple of days. The effects are quite stunning.
Setting the scroll increment to 5px diminishes the lenticular effect; it's like skipping frames in film. Your mind interpolates the result, but it's not as smooth as scrolling by 1px and reducing the time interval to speed things up instead.
Try this one instead to see the difference. This will scroll at approximately the same rate as your example:
I'm curious what browser you use. I was under the impression that most of the major browsers had disabled the ability to type javascript: URLs because of self-XSS (which is a fascinating concept on the border between computer exploit and human exploit).
On Chrome 39 on CrOS, I can't type that into the URL field, and if I copy/paste it, the "javascript:" portion of the scheme magically disappears, so hitting enter takes me to a SERP. I wonder if that's done in the hope that you Google the self-XSS that you were about to run and see someone explain what's going on.
I am lazy and suck at scrolling smoothly, so I middle-click to get the scroll tool set-point, then move my pointer a little below the set-point to indicate that I wish to scroll down slowly. Works in FF and Chrome.
Middle-click usually pastes stuff you selected on Linux, so not everyone.
However if I enable autoscrolling then middle-click works as you described, quite useful!
To scroll super-slowly and smoothly on Windows, use the middle-click thing that spawns a little arrow-circle doodad. I'm pretty sure Linuces are inconsistent about implementing that feature, though.
Ah, thank you! My scrolling is just too spastic :)
Does anyone besides me have a problem with the pictures being too large and too close together? The mask lines were only in the top half of the screen and I could never see the entire picture onscreen as they were too large. Zoom out did nothing.
It's an option in Firefox, which (IIRC) is disabled by default everywhere except Windows. Look in Firefox's preferences; on the Advanced tab, it's the "Use autoscrolling" option.
Middle-click-to-instacopypaste-highlighted-text is a well-established standard on Unix/Linux and people are highly resistant to losing it.
I like the Windows convention that the middle-mouse is entirely for navigating the viewpane, so I'd prefer if it was just ctrl+command+click or something for the "selection-paste" operation, but that kind of UI change is a hard sell.
Am I doing something wrong? I don't see anything interesting. I see black lines and some art scrolling behind the lines. Is there some sort of illusion this is supposed to create?
I see, you have to use the scroll bar which goes one pixel at a time. This doesn't work for me if I use my scroll wheel on my mouse. It works if I grab the scroll bar and move downward.
Moiré patterns are about superimposition of periodic patterns.
This has nothing to do with it, it's just dividing an animation into scanlines and interleaving them so that the horizontal lines act as a shutter when scrolling.
would also relate this to the technique of interlacing[1], which I find in this case even more relevant than the very special application of a moire pattern. Just that this one has more than the usual two fields.
Basically you're moving an interlaced still image composite made from multiple frames of an animation under an stripe mask revealing only the current frame, where the ratio of stripe to black equals the number of frames.
Lenticular prints[2] work in the same way, but instead of a mask the lenses blow up each line to full width (much like an optical equivalent to line doubling video deinterlacing), trading resolution in one dimension for encoding multiple frames.
When I came back to HN, I noticed that my mind made my vision appear actively "wavy." In other words, I could see some slight movement of waves on the horizontally drawn elements currently displayed -- the top orange bar that says [Y]Hacker News [...] had the appearance of fluctuating with low frequency waves.
Trying this with different browsers on Windows highlights how bad the pan acceleration curves are in Firefox and Chrome. In Chrome there are exactly 2 speeds where this works usefully, and they're a pixel apart. In Firefox there's a small handful of them, and you have to be fairly careful with your mouse.
In Opera 12 on the other hand there's a range of about one inch of mouse movement on the screen, where you get, pixel-for-pixel, different speeds for this thing, all of them useful.
Ah, palette shifting, that takes me back... but man, Mark J. Ferrari, truly a master in the 8-bit field. Really took palette shifting to another level. And the site does a great job exposing what's going on under the covers. Great link!
I created a webapp for fun some time ago, is somewhat minimal but explores how to do this effect easily from a bunch of images or shots from the webcam (applying cool filters!), the js sources are not compressed so you can read what is going on http://animotion.licheni.net/
Agreed. I wish people gave a little more warning prior to showing pages with rapid changes in luminescence. You're talking about a really rare type of epilepsy - but frankly, it's so easy to add a non-triggering splash screen that everyone building something like this should do it. There's no excuse for giving even one of your users brain damage.
This is great. Reminds me of a certain kind of chain email that I would commonly receive from friends in the late 90s, although I imagine that they likely existed before that time as well.
You would get these emails that were thousands of lines long with ASCII characters all over the place. When you'd scroll, though, an animation would take form and you'd watch stuff bounce left and right across the screen and other effects similar to, but more primitive than, the effects demonstrated by this submission.
This reminded me of a toy I had as a kid: the Tomy Tutor Play Computer. The screen was a lenticular lens over a paper scroll, and pressing the space bar caused the lens to move vertically.
Yes! I just got this for Christmas. Granted, I showed it to the person who gifted it :) I still loved receiving it and have spent a lot of time with it.
I have no idea what is going on but sure had fun scrolling slow. Well worth my time. Props to the founders for launching. It is a hard field to compete in but I am sure they will find their revenue model.
