Comment by CapsAdmin | Hacker News Reader

Comment by CapsAdmin | Hacker News Reader

Some of the sound descriptions in this article sounds very similar to an on going experience I had, although without the health problems (I hope?)

It turned out to just be a bad phone charger. I would charge my phone at night (samsung s4 at the time) and when fully charged and idle it would make a very high pitch and faint sound that sounds like "morse code" or digital noise (I believe the sound characteristics is the CPU doing stuff and drawing power?)

The sound was only be audible in some places of my appartment and it would depend on how my head was turned. I remember hearing this sound even in my dreams.

I've heard this sound outside as well depending on how I turn my head. But lately I haven't heard or maybe noticed anything. I'm also getting older though so maybe I've lost the abiltiy to hear high pitched sounds like that.

Googling "keep hearing morse code" and similar terms reveals that many people have had similar experiences but many wild conclusions.

There might be something shady going on in Cuba but it wouldn't suprise me if bad adapters and sockets would get lumped together with it.

That's just a coil or capacitor vibrating at high frequency. The switch mode power supply changes frequency depending on the load, and when your phone is fully charged the load is low so the normally-ultrasound drops into the audible range.

Nearly all chargers get like that eventually, I guess as the glue or capacitors start to fail.

The reason you can only hear it in some places is because it causes standing waves, and you move your head in and out of the nodes. Basically constructive and destructive interference.

Anyway it is almost certainly totally unrelated. It's always very quiet and doesn't cause any brain damage or any other symptoms.

The more likely explanation for why you hear it in some locations and head orientations, is that the volume is right on the threshold of your ability to hear it. By turning you head, or obstructing the direct path, it drops below your sensitivity threshold. I have a ticking wristwatch that demonstrates this effect very well.

That could be the case sometimes but not usually for high frequency whines. They're can be pretty loud and annoying, and they fade in and out simply by moving - not turning - your head.

A common cause of this especially in power supplies is "coil whine", and it's caused by someone choosing a PWM frequency for their design in the audible range, or the design emitting harmonics in that range.

A painful number of my electronic devices also do this: cell phone charger, laptop power cord, electric toothbrush, surge protector, ...

I go around the house unplugging them at night, and try to keep the doors they're in shut during the day, so the cat doesn't go insane. I'd pay for an ultrasound detector to actually identify remove the buggers permanently, but sadly, my amazon-fu is coming up short.

I had something making a loud sharp continuous 16 KHz tone in my house in the living room, at least according to an audio spectrum analyzer app.

I'm old enough that 16 KHz is outside my range so it never noticeably physically bothered me. I don't remember for sure, but I think I tracked it down to my TV.

That TV died a few weeks ago and I replaced it. I just checked, and there is no more tone.

Was this old enough to be a CRT TV? Their flyback transformers [1] very often emit a sound of 15.6 kHz, which is very obvious to all younger people and unnoticeable for older folks. I feel I was especially susceptible to this noise, and would frequently change rooms to escape it if the TV was on.

I whole-heartedly welcomed the change to flat TVs and monitors.

[1] https://en.wikipedia.org/wiki/Flyback_transformer

The old TV was a flat screen. Samsung UN55B6000.

I get something very similar from my laptop. Only hear it if in a really quiet room. I thought it might be from my SSD but discussions online seem to indicate some sort of high frequency vibration somewhere else in system. Will try unplugging next time I hear it.

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