Audio interference in car

Discussion in 'iPhone' started by Michael CM1, Jul 14, 2011.

  1. Michael CM1 macrumors 603

    Feb 4, 2008
    I have an iPhone 4 and use a Magellan GPS dock for a speakerphone, charger and to output audio to my car's sound system using a cable with 3.5mm jacks. However, this was true before when I just used any cable to plug my phone up and charge it during driving.

    When charging the phone, I get this annoying high-pitched hum through the sound system that goes along with my engine noise. So if my car down-shifts, you can hear the hum change with it. It's not so bad on a lot of stuff, but on things like classical music that require a higher volume, it can be unbearable.

    I wanted to know if anybody knows a good way to get rid of this interference. I know you can get rid of GSM buzz on computer speakers by using iron ferrite beads on the speaker cables, but I don't know whether that would help in my car. It's directly related to the phone getting charged, so I'm at a loss as to how to do this without unplugging it. The GPS cradle won't do anything if it doesn't get power to it, so that's not an option.
  2. kfergiez macrumors 6502


    Jul 5, 2010
    Ferrite beads on your power cable might work. The problem is in the way power is transferred in the car. 12 volt DC isn't the the cleanest way to transmit power. The other problem is the the shielding of the power cable. Not much you can do about that.

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