(Untitled)

[tymothytoastman]

Can anyone else tell when CRTs are on in the next room, or do I just have the stupidest mutant power ever?

There has to be some kind of bio/psychological reason for it.

Comments

[marcmagus]

I can hear it sometimes. I believe it's caused by either the horizontal or vertical refresh; I'm not sure which and I don't know the frequencies of either off the top of my head, so I can't really guess. IIRC, the electron gun stops while it's tracking for the refreshes, which sometimes creates a slight sound; since the periodicity is quite perfect, some people hear it as a pure tone hum.

[tymothytoastman]

I think it's 60Hz, or some other magnitude.

[carybella]

Don says he used to be able to tell when a CRT was on in the other room.

[lepidus]

I can tell. For roughly the same reason that I can also hear dog whistles. Sadly, I can do neither as well as I could when I was younger. As we age our ability to hear high pitched sounds decreases.

There is/was a mall parking lot in the UK that used this to discourage teenagers from hanging out. They had speakers playing sounds that drove away younger people, but were too high to be detected by most adult ears.

[driftingsoul]

anywhere in the building! though as lepidus has pointed out, this has lessened with age...

[electrolite37]

I can tell when old skool TVs are on. The flat screens confound me. I also have sensitive hearing (the type that makes me wake my husband in the middle of the night confirm or deny a sound).

[tymothytoastman]

old skool TV = Cathode Ray Tube (CRT) = old skool comp monitor. I don't think the same thing happens with flat screens, especially if marcmagus is right about refresh rates. I believe that Flatscreens don't have a "refresh" - pixels are just "on" or "off" with light bulbs behind them.