Strange buzzing sound coming from LCD monitor

[Nevander]

Randomly discovered something strange...

So apparently if you have borders in Excel, even without the whole entire sheet being bordered, AND have the screen zoomed or set to a certain size (such as 10 font size), your LCD monitor will emit a very faint buzzing or humming sound.

You can observe the behavior and test it by making a new sheet, setting the entire sheet to be all bordered and setting the sheet's font size to 10 in all cells. You can clearly hear the sound here under these conditions.

Moving the window off the screen will make the sound go away.
Highlighting all cells (or majority of them) will make the sound go away.
Moving a window in front of the Excel window will make the sound go away.
Changing font size or zoom will alter the pitch of the sound.

If you change the border color to a lighter black or closer to white, the sound gets quieter until gone.

Surely this isn't just Excel, and has something to do with the alternation of black and white colors on the screen. Could anyone offer up a scientific explanation?

[edward850]

You keep saying "your monitor" without thinking that maybe it's just the cheap monitor you bought. This certainly doesn't happen on my monitors.
Each row of pixels you have on screen has a voltage applied for each cell, however you keep changing the voltage between rows the most abrupt way possible (black-to-white). There is a component on your monitor that isn't designed to handle this perfectly, the resulting changes produces sound, and the constant changes produces a recognisable sinewave. Whichever component this is can range from the power supply to the LCD itself.

[Nevander]

I don't think a $400 monitor counts as "cheap." Are you saying this is a defect?

This person had same problem AND discovered the same thing as me: https://www.reddit.com/r/excel/comments ... l_ss_open/

[edward850]

It does depending on what your requirements are, although in hindsight you haven't described how noticeable this hum is, which does play a factor. It's very easy to reproduce here, but how much depends on build quality, signal quality (VGA or HDMI) and even your age. I can actually reproduce this on my old AOC, but the noise is only based on movement and is actually too quiet to hear without putting my ear on the monitor.
I don't get this on a 1 grand screen, however, and at that price you're paying for the best possible screen already (and neither my laptop).

[Nevander]

I see. Like you said, I have to actually put my head close to the monitor to hear it easily. If I were just doing my work I wouldn't really notice it enough to care, but it can be heard from a normal distance away. I'm 25 and it's easy for me to hear if I really listen for it. I can definitely hear it using that page. It only gets loud when the bars get almost as thin as they can and then quickly goes away. Seeing as how the page actually states it can happen on "some LCD monitors" must mean it's normal under certain conditions on those monitors, such as the ones the page (and Excel) produces? I just don't want it to be a defect.

I suppose I could change my borders or their color.