Mobile Phones and Computer Speakers

Recently I’ve noticed that my computer speakers have been making strange "Bzzz" sounds periodically. I tracked down the cause to my mobile phone; I now place the mobile phone away from the computer and the sound has stopped.

This isn’t an ideal solution because the phone will need to be placed by the computer in order for data to be transferred or for the phone to be charged.

I did notice in the user manual that the mobile phone shouldn’t be used near computers but I suspect that this is simply a disclaimer for the manufacturer just incase anything does go wrong.

Has anybody experienced anything similar with their mobile phone? Are there any ways to prevent it? 

12 thoughts on “Mobile Phones and Computer Speakers

  1. Phones will do it when placed next to any speaker and the phone sends/receives data. If you put it next to an old CRT monitor, you also get interference on the screen when data is transferred. There’s no way to avoid it.

  2. Dunno if you’ve noticed that during a French exam on the tape player sometimes there was a morse code like beep sound – usually someone’s phone. Funny when a few go off consectutively. 

  3. Hey Khlo, haven’t read this Blog in a good while!

    I’ve had similar problems with EMF/RFI since changing headphones about a year ago. After getting fustrated with the constant electrical noise whenever anyone was on the phone – I did a little research. Although I couldnt find any ways to completely irradicate this (other than changing phones), I did find a way to reduce it significantly. This was by coiling my Headphones wire around several Ferrite Rings, which basically act as shielding. It’s not an ideal solution but it does help, and is relatively cheap.

    I think these are what I bought:

    http://www.maplin.co.uk/Free_UK_Delivery/Ferrite_Rings_29788/Ferrite_Rings_29788.htm 

    Hope this helps!

     

  4. this happens to me…

    In my case, it’s caused by the mobile phone signal interfering with my sub-woofer, which is not electromagnetically shielded.

  5. Never had this problem, it’s possible my speakers are shielded, or maybe no-one wants to talk to me.

    Cover most of your speakers in depleted uranium, that should stop the interference.

  6. Putting your phone in some metal container always helps, you can’t receive messages/calls meanwhile if you overdo your shielding though.
    Also try placing your phone under the  screen and calling it.  This is really nice, if the screen starts kind of flashing ^^ 

  7. It’s strange you’ve never noticed this before. Mobile phones inteferre with TV’s, speakers, radios etc. etc.

    I have decent speakers to be honest, and my mobile phones inteferre with them more than previous ones as the pre-amp seems to be susceptible to the inteferrence, passing it to the amplifier and causing the speakers to nearly blast a hole through the wall.

  8.  Its due to the amplifier in the audio speake,r  that somewhere in the amplifier or before, picking up the radio waves and amplifying them so you hear a sound at the speaker. If it was after the amp stage it wouldn’t be too loud and computer speaker wires are usually coax which would probably reject the radio signals. I could be wrong. I know that when I turn on my cell phone I can hear a series of beeps in my computer speakers even if the computer is off because the amp stays on when the computer is off It is an effect of the non-linearity of the first stages of the amplifier. What actually happens is that when high-frequency signals are seen by the entrance of the audio amplifier, the amplifier cannot follow the very high oscillations. Normally,it gets filtered out. That is correct if the entire system is linear. But the signals from a cellular phone are MODULATED high-frequency, and due to small non-linearities in the amplifier, you change slightly the operating point because of the incoming signal. Now, that, in itself would not be a problem, but the movement of the operating point follows the modulation (it moves, say, slightly up when the signal is present, and moves down again when the signal is not present). And as such, the modulation signal becomes amplified.

    It is exactly the same principle as an old AM radio, where you use a (non-linear) diode to "detect" the modulation. Given the rather high power a cellular phone uses for his broadcasts, this is seen by the audio amplifier. Any AM radiostation nearby would do the same. FM wouldn’t because the envelope is at almost constant level and hence the sound of noise is same as u said …tatada taatada

    tatada taatada tatada taatada

     

    the best way to use the shileded spaeakers and good coaxilal cable to avoid it …

  9. This is quite strange.Are you sure it is because of your mobile phone.
    Because i checked mine and it’s not the case with me.

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