

Ask HN: Why do my speakers make a weird noise near a phone? - dsc

What does this represent?<p>It usually starts when someone is about to call. But sometimes it goes off and no one's calling(that's scaring me).
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_0ffh
It's electromagnetic radiation from your phone. When you're about to be
called, it will pick up the call request from the cell station and answer the
request. The EM radiation from the phone induces a current in nearby cables,
which is transformed to sonic waves by the speakers.

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dsc
Hmm I'm kinda concerned that someone might be spying on me :)

But yes, I saw both your comments and "sometimes it does it for no reason" is
still scary to me.

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coryl
Could be your phone being pinged in order to keep tabs on your location. I
would throw the phone away and change your identity. You must have upset
someone in the government.

That or its nothing at all.

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wrs
That is the "GSM noise" (<http://www.corporatetalkradio.com/thatnoise.html>).

Slightly OT: One of my favorite easter eggs in Grand Theft Auto IV is that the
GSM noise plays just before the in-game cell phone rings. That really had me
confused for a second.

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mahmud
Ages ago, I had a Nokia phone with a now defunct U.S. provider called
Voicestream. I could hear the callers talking before I picked the phone.
Sometimes I would hear "He is not answering", but in a few occasions, I heard
horrible things :-)

I don't even know how that's technically possible. I held on to long after the
handset was out of fashion.

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_0ffh
Oops, I forgot: Sometimes your phone will make contact with the cell network
for no apparent reason. Don't be scared! =)

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protomyth
What type of phone and what brand / model of speakers? The iPhone is kinda
known for doing this to speakers.

[edit]
[http://www.iphonematters.com/article/speaker_interference_th...](http://www.iphonematters.com/article/speaker_interference_the_real_iphone_buzz_217/)

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schindyguy
I have heard you can remove that noise by putting magnetic snap things over
the power line of the speakers you have. It looks like a capsule that opens
halfway and then you snap the cord in between. I have a ton from old
plasma/lcd installs as most people just throw them away in the box.

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Rust
I've owned some Sony Ericsson models (the old T610 comes to mind) that were
actually well shielded and wouldn't cause any audible interference with
speakers.

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_0ffh
Sorry, but that just doesn't make much sense. The phone "wants" that radiation
to go out, since it uses it to "speak" to the cell network. Shielding that
radiation would be like gagging yourself and then trying to talk to someone...
What makes a difference to the audible sound are mostly carrier frequency,
pulse frequency and, yes, field strength (but you still wouldn't want to
suppress that by shielding it).

~~~
Rust
Whatever the case, that phone never caused any audible signals in my speakers
:)

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Indyan
Yeah..this also happens with my phone. Usually just about 5 secs before a call
or SMS is received.

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joshu
Cdma phones don't do this.

