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How to Avoid Mobile Phone Interference w/ Speakers

Posted by ryuzaki0 on from the nextel-phones-are-the-worst dept.

EnzoTen asks: "Everyone has been sitting at their desk rockin, jamming, or groovin to their favorite tunes. You are in a trance, getting work done... then... BZZZPT... BZZTP..BTT.. BZZZZZZZZPTT... the blood curdling noise of your cell phone interferes with your desktop speakers playing 4 times the volume of your music and it takes everything in you not to flip your desk upside down, or throw your mobile phone across the room. Is there anyway to avoid mobile phones interfering with speakers? Are there speakers available that are shielded from this type of interference?"

2 of 228 comments (clear)

  1. GSM by Detritus · · Score: 4, Insightful
    It seems to largely be a problem with GSM handsets, so users of handsets that comply with other standards may not notice a problem. GSM uses TDMA, and has also been noted for interference to hearing aids.

    The solution is to properly shield the speakers and speaker wire. The speaker wire behaves like an antenna, coupling the signal into the audio amplifier, where it is detected and amplified. It's behaving like a crystal radio, a primitive type of AM radio receiver.

    --
    Mea navis aericumbens anguillis abundat
  2. Re:Never happened... by dscho · · Score: 5, Insightful

    Slashdot comments at its best. Useless.

    If you do not recognize the problem, it just might be that you

    a) do not experience it -> cannot help.
    b) do not hear it -> cannot help.
    c) notice it, but do not want to help!

    In every case, it might have been a good idea to wait and see if more
    intelligent and/or helpful people chime in, and might provide an answer to
    the riddle. And until that time, just shut up. You probably will just look
    foolish if you try otherwise .

    I actually *understand* the physics behind that phenomenon, and alas, there
    is no better solution than what was provided in another response: put your
    cell phone at least one foot away from the speakers. The problem is Maxwell:
    in order to send a signal successfully to the next station (remember: this
    is most likely indoors, as speakers are less usefull outside, and thus, there
    is probably a wall, which has to be penetrated by electromagnetic waves) the
    cell phone has to "pump up the volume".

    The energy is degrading with the second power of the distance to the cell
    phone, so: putting it at double distance to the speaker (or the next
    station, for that matter) will lower the received energy by 75%. Same is true
    for the station, but that is farther away to begin with.

    educating people every day,
    Dscho