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I was sitting on my chair in office when my cell phone rung. Somebody was calling me, so there was a caller tune which was played.

But then I realized my speakers were producing strange sound when my phone was ringing.

My friend said It was because of disturbance produced by radiowaves. But even he was not sure why it happened.

Do anybody know the possible cause that made speakers make strange noise.

It only happens when there is a call or message on my cell phone, not when I play any song etc on phone

Here is a sample of the similar kind of noise that was created from my speaker

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It is the principle that every receiver is also an emitter. That is how one can tell what program a television is tuned in, with accurate enough instruments.

Your cell phone has a receiver of the incoming electromagnetic radiation . That is also an emitter ( by the way the circuits work) that is quite close to the speakers.

I have a similar effect with an old TV, which as long as it is on buzzes when my cell phone is in the same room, (close enough), with the buzz the cell phone sends for its location.

Not to forget the 1/r^2 diminution of the energy any antenna signal in these handwaving explanations. These effects need the cell phone fairly close, and the speakers ( of my tv too) be resonant to the frequencies . As the signal isdigital the carrier frequencies are caught and turn into noisy sounds.

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  • $\begingroup$ This is true, but it's not the reason. As mentioned in a comment by @RedGrittyBrick to another answer, cellphones have explicit radio trans,itters in them, and it is these that you hear the effects of. $\endgroup$ – tfb Feb 3 '17 at 8:13
  • $\begingroup$ @tfb whose comment? $\endgroup$ – anna v Feb 3 '17 at 8:15
  • $\begingroup$ @tfb that is what I am saying with "every receiver is an emitter" If it can receive a radio signal it also emitts it at that frequency, when it responds to the incoming.. $\endgroup$ – anna v Feb 3 '17 at 8:17
  • $\begingroup$ sorry, I botched editing my comment multiple times: it now mentions the comment author & that it was a comment to another (the other, as I write this) answer. $\endgroup$ – tfb Feb 3 '17 at 8:17
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    $\begingroup$ Anna - in this case it is the fact that a cell phone has a transmitter in it that communicates with the cell tower. The fact that "every receiver is a transmitter" (see this wonderful article from 1922 Popular Science is not relevant in this case. See this question $\endgroup$ – Floris Feb 5 '17 at 20:05

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