Cell phone turning my subwoofer on!

Discussion in 'Speakers' started by JasonMA, Feb 3, 2004.

  1. JasonMA

    JasonMA Stunt Coordinator

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    Anyone else having this problem with their powered subwoofer? Whenever my cell phone rings in my HT room, my powered subwoofer turns on and hums, even if everything in my HT is off. It's not a very loud hum, but it isn't low either. It doesn't sound like something that is damaging the sub, but I'm not sure. I have tried to keep my cell phone as far away from the sub as possible, but unless I put it in another room it still has this effect on the sub. I don't want to have to miss all my phone calls when I'm in the HT room, but I don't want to ruin my sub either. Any thoughts.

    By the way, the sub is an Athena AS-P400 and the cell phone is a Nokia 3520.
     
  2. Baldemar Garcia

    Baldemar Garcia Stunt Coordinator

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    I'll have to ask a friend if his sub has this problem with his new Nokia. But I do know that the phone makes his car stereo and his desktop speakers 'hum'.
     
  3. JasonMA

    JasonMA Stunt Coordinator

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    I've seen all types of cell phones make speakers hum when they are turned on, and even affect the monitor to my computer if they are close enough, but my cell phone is actually switching my powered sub on and then making it hum. This particular sub doesn't have a power switch so it just turns on when a signal is received, like most powered subs out there, but to turn on when a cell phone rings? I've never experienced anything like this before.
     
  4. Dan Halchak

    Dan Halchak Stunt Coordinator

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    Your cellphone is creating enough "interference" in the line to your subwoofer that is great enough for it to think that there's an incoming signal... I'm assuming you have it set to auto on, not have to turn it on (because then yes, that's just freaky). Once the sub turns on it sees this signal and does it's job, amplifies it. Which gives you that hum.

    My old cell phone did that with my Computer speakers, it would make them hum anytime they were on and a call would come in or I would be on a call within about 3 - 5 feet of them.

    Unfortuneately, I couldn't find much that one could do but move further away from the speakers.
     
  5. Alan M

    Alan M Second Unit

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    Interesting post Jason.I have the athena P-2 sub.When I plug my cell phone(samsung)in to charge at nite,if I put it near my sub,It will turn it on.This is with my cell powered off.
    I have since moved the location where I charge it at nite.Thought it was only me experiencing this phenom.Hope you solve the problem.
     
  6. Doug_H

    Doug_H Supporting Actor

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    If the interference is getting picked up by the subwoofer cable you might try one with better insulation. Aside from that I don't have any solutions. Interesting problem though.
     
  7. Jeff W.

    Jeff W. Stunt Coordinator

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    This happens with all powered speakers and all cell phones. Computer speakers, subwoofers, etc...

    You just have to move the phone farther away.

    Some phones are worse than others. My old Nokia wasn't so bad, but my new Nextel is stronger or something and does it worse..
     
  8. JasonMA

    JasonMA Stunt Coordinator

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    Hmmm, I don't really want to have to spend more money on a better cable. The one I have is a Monster THX subwoofer cable. Can't remember what I paid for it right now, but it was expensive enough to not want to upgrade it just yet.

    I guess this isn't a unique problem though as others have stated. I'll just try to keep the cell phone away.
     
  9. Chris A H

    Chris A H Stunt Coordinator

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    I don't think this is so. Can place my Nextel phone right next to my SVS PB1-ISD with a home-made RG59 shielded cable and nothing happens when it rings. Same for my older Nokia.[​IMG]

    I would say the sub amp does not have enough shielding in it's design or the cable is not shielded adequately.

    See this article on hum rejection testing of sub cables.
     
  10. Eric Eash

    Eric Eash Second Unit

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    i think running it through a good power regulator should do the trick. at work, we use walkie-talkies that are real powerful, and all the computer speakers hum when keyed. we can even put them up next to a turned off flouresent light bulb, and when keyed, it will light it up.

    eric
     

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