24" Aluminum iMac Headphone Weirdness

Discussion in 'iMac' started by arsenalgear, Apr 13, 2008.

  1. arsenalgear macrumors member

    Dec 17, 2007

    I have a strange issue when I use headphones with my 24" aluminum iMac. Before my computer outputs any sort of audio, it is proceeded by a light quick blip or pop. After audio is played, a ringing in the right or left earpiece or a sound like an open phone line can be heard. Even when the system sound is muted, i can hear ringing following audio. These noises last for about 30 seconds or until more audio is played.

    In addition, sometimes when a flash video or a Quicktime movie is loaded but not played I can hear ringing in an earpiece.

    I have tried three different sets of headphones (all of which were tightly inserted) and a clean install of Leopard on an external HD but the problem persists.

    Has anyone experienced anything like this? Is there a way to clear it up???

    Thanks :apple:
  2. Bobbi Flekman macrumors regular

    Jan 14, 2008
    Is that "blip" everytime? I mean play an .mp3 and it is blip > mp3, then the next song comes up and once again it is blip > mp3, or just the one time? Is that blip also audible on the systems internal speakers?

    I have a 24" iMac as well and it is hooked up to a stereo amp through the headphone output. I never hear something out of the ordinary. When I reroute the audio to an external Audio interface (MOTU 828 MkII) I don't hear any weird artifacts either.

    How old is the computer? Has it been doing this from the start? Have you updated all programs and firmware? Have you gone back to have it checked out?

    As you've tried it with several headphones either the audio interface is busted (which would be shown through the use of the internal speakers), or the output jack is busted (though I find that hard to believe).
  3. arsenalgear thread starter macrumors member

    Dec 17, 2007
    Though it blips or beeps often before audio, it is the sounds once audio stops that is most annoying. It doesn't happen with subsequent music tracks. I notice it most with application sounds, like mail retrieval and people switching their iChat status - short quick sounds (though pausing a track in iTunes can cause it too, along with loading but not playing a video).

    Basically it goes more or less like this: beep > computer audio > ringing or low white noise sound. This lasts for about 30 seconds or until another sound is played.

    The first time I heard the ringing I tried popping my ears, thinking they were plugged. :) It is subtle but annoying.

    The problem doesn't seem to manifest itself with the internal speakers or with my external USB SoundSticks.

    The computer is about 4 months old, but it is only recently have I had a chance to really use it. Just last month it was in for repairs, as I was having extremely loud static with the built-in iSight and they wound up installing a new power supply and mic cable.

    Is there a possibility that the headphones could be picking up internal noise from the computer?
  4. Bobbi Flekman macrumors regular

    Jan 14, 2008
    Ho.... Wait.... Is this a wireless headphone? If so, try it with a headphone that has wires. I had a wireless once and that exhibited the same behavior you mention. Blip.... (the thing turns itself on).... sound from the television ( I had it hooked up to that)... turn your head or walk out of the room (out of the wireless range), and static exploded!

    Somehow I hadn't expected someone to use a wireless with a computer.;)
  5. arsenalgear thread starter macrumors member

    Dec 17, 2007
    Nope, wired. I've tried two sets of Sennheiser PX100 and Apple in-ear headphones. The noise is most noticeable with the in-ear ones.
  6. jf8 macrumors regular

    Aug 8, 2007
    My 20" aluminium iMac does this, even in Windows Vista with the latest available Realtek drivers.
  7. arsenalgear thread starter macrumors member

    Dec 17, 2007
    Is this something that can be repaired or are all of the aluminum iMac models like this??? :eek:

  8. Bobbi Flekman macrumors regular

    Jan 14, 2008
    Weird... As I said I have an aluminum 24" iMac as well, and I don't notice anything. I would go back to the store (take one of the headphones with you), and let them look at it.

    Sorry I can't be of more assistance :(
  9. NMW3713 macrumors newbie

    Mar 11, 2008
    I could have swore mine also did this the other day, not the blip before the Audio, but right after the music was done there was a slight high pitch ringing sound when i was wearing my Sony studio headphones. The sound wouldn't increase when i turned up the volume either... now ever sense i haven't heard it again? sorry i am of no help :eek:
  10. AndroidCZ macrumors newbie

    Apr 17, 2008
    Brno, Czech Republic
    Same problem

    I have the same problem (with high pitch sound) after end of some audio playback. It's usually in one channel only - sometimes in the left channel, sometimes in the right. It disappears when any new sound output is present, or when I change the output level.
    And yes - sometimes I have the "blips" too!
    I'm a little bit dissapointed by AL iMac sound performance and still looking for solution :(

  11. rozwell macrumors regular

    Apr 17, 2004
    I have this issue on a White Intel iMac (last revision) and I have just accepted I cannot ever use headphones or external speakers :/ It shouldn't be this way, but it is.

    On a side note, I have a MacBook Pro at work with the same issue too (second to last revision) where its particularly annoying since we all listen to music via headphones. Again, you just deal with it unfortunately.

    Its probably some poor choice of hardware components or some internal interference. I have tried turning off all wireless devices and internal components (AP, BT) and it still has the issue. Something I read a while back suggested playing a silent sound continuously in the background to fix the issue so that the sound card never actually stops producing a signal. I bet a small Air app or even a widget might be able to do the job.
  12. arsenalgear thread starter macrumors member

    Dec 17, 2007
    Wow, these last two replies are exactly what I am experiencing! It is a good feeling to know that I am not alone at least. ;)

    Have you contacted Apple about this issue?

    BTW, what is an "Air app"?

  13. rozwell macrumors regular

    Apr 17, 2004
    Air is a product from Adobe. Its a cross platform way of deploying "applications" or widgets. Since its either HTML, Flash or Flex based its super easy to develop. When I get a free moment I might give this idea a try.
  14. applec2400 macrumors newbie

    Jan 13, 2008
    I have the same problem.

    Whenever there's no audio playing in the headphones I get a real high pitched tone playing in the headphones. My assumption is that it's a firmware issue and when there's no audio the card doesn't really know what to do because it disappears as soon as there's a signal (audio playing).

    I currently have a 20" Aluminum iMac (April '08) bought as an "Apple Certified Refurbished Product". It's 2 weeks old :(
  15. rfruth macrumors regular


    Feb 5, 2007
    do people think a referb is a cream puff that know 1 else wanted :confused:
  16. n00n00 macrumors newbie

    Oct 31, 2007
    I get this also on my 20 inch alu imac when no audio is playing
  17. antonispegasos macrumors newbie

    Jun 26, 2009
    I know what you're talking about. Just unplug any firewire connection you have on, and voila...! :)

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