Ask HN: High-pitched noise when lots of colored text shows in terminal over SSH | Hacker News Reader

Ask HN: High-pitched noise when lots of colored text shows in terminal over SSH

1 pointsvl4 comments

So my Google-fu is completely failing me here.

I SSH into a server, where I run a grep --color=auto, matching about a third of its output (so nearly a third of the screen is showing colored text). Whenever the terminal showing this output is visible on screen, my monitor emits a barely audible high-pitched whine (which, as soon as I noticed it for the first time, became highly annoying). Alt-tab away, the sound stops immediately. Run a command showing non-colored text, the sound stops immediately. I can reproduce it with other commands showing colored output (cd /; ls; ls; ls; ls, etc). I'm not hearing it if the amount of colored text on screen is low (cd /; ls -al; ls -al). I've changed GREP_COLORS to show non-bold and non-red colors; doesn't make any difference. This _doesn't_ happen in a local terminal; only over SSH.

OS is Ubuntu 12.04 (both client and server), monitor is a Samsung Syncmaster 215TW.

I'd like to make the noise go away, without losing the benefit of colored output, but I'm utterly clueless on how to proceed from here, or even where the people who would be likely to be able to say intelligent things about this would hang out. I'm hoping someone here could give me a first pointer...

> This _doesn't_ happen in a local terminal; only over SSH.

That is odd.

Are the colours the same locally -v- over ssh? I don't just mean "is the text red?" I mean: what are the RGB components of local red? Are they the same as the RGB components of red over ssh? (I don't know of a better way of checking this than examining a screengrab with an image editor.) Similarly for other colours. We would expect local black to be the same as black over ssh, but local red to be different from red over ssh.

Do you get a whine when a local terminal shows coloured text, while in a different window you are sshed into a server without coloured text?

First, find out the reasons a monitor would make a high pitched noise, then work backwards to find out why this happens in your colored output scenario.

I think it might have something to do with capacitors, I had problems with my video card or mobo making high pitched sounds and I think I remember reading that the capacitors were making the sound. It only happened when entered a game or app that made heavy use of 3d rendering.

So my guess is the app that outputs in color is making your monitor or video card enter a state that uses a lot of power, or otherwise for some reason causes the high pitched sound.

I could be totally wrong though.

http://www.silentpcreview.com/stop_lcd_whine What happens if you increase the brightness

My monitor brightness is indeed set very low (2/100), but increasing this to 100/100 doesn't change anything (nor does fiddling with the contrast). Don't think it's _purely_ a hardware problem anyway, since a regular terminal doesn't show it; only a terminal in which I'm running over SSH. Thanks for the suggestion, though!

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