Random pop sound

Discussion in 'iMac' started by DJJAZZYJET, Aug 2, 2011.

  1. DJJAZZYJET macrumors 6502

    Jun 4, 2011
    Wirelessly posted (Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Mobile/8J2)

    Hey good forum folk, i need some help. I just shut down my imac and for some reason it took longer than usual (normally its within a few seconds) but this time it took about 20 seconds, then as the screen shut off the imac made a 'pop' sound. This has never happened before, i turned it back on and it booted fine and took me to the login screen. I hope this isnt to serious, this is a new 2011 27" quad i5 3.1ghz 12gb 9670m 1gb machine 1tb hard drive osx lion spec machine??? Thanks in advance.
  2. macdudesir macrumors 6502

    Jan 16, 2011
    Blacksburg, VA
    Sounds normal to me....it happens to me sometimes (though not on shutdown with the apple logo only on kernel panics.......) it must be something with the speakers...
  3. drambuie macrumors 6502a

    Feb 16, 2010
    The pop was caused by the sudden removal of power from the audio amplifier. To prevent pops when power is applied to, or removed from an amplifier, the input is quieted, or clamped to ground level, to allow the power to stabilize on power on, or quieted before power is removed. On sound systems this is done by the amp's firmware, but with the Mac it's obviously done by software, since it looks like your unusual shutdown allowed power off without first quieting the amp. On a computer it's just an annoyance. However, if you're dealing with a 500 watt power amp, the pop could blow a speaker.

    I have a Viewsonic monitor with audio that does this. I always turn off the computer before the monitor, so the monitor is in a sleep state. If I then turn off the monitor by its switch the shutdown firmware prevents a pop. I always turn it off by the UPS switch and the monitor gives a pop after a couple of seconds, when its power supply voltage finally drops to zero. The monitor is going on five years old, with no harm done by the pops.
  4. DJJAZZYJET thread starter macrumors 6502

    Jun 4, 2011
    I think its fine..

    Yeah i agree, its defiantly just something from the speaker. The pop wasn't very loud, and i have some 2.1 speakers that pop almost every time i turn them off, no biggie, it hasn't done it again or seemed to have affected it in any way. Thanks :)

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