Sometimes my MBP plays this somewhat distressing sound through its speakers (external if connected, otherwise internal, if my system volume is not muted).

Has anyone experienced this? What is it?

[Listen to the sound here.]

Things that make me doubt it has to do with the electrical system:

  1. The fact this seems to be emanating from my system (affects either internal or external speakers)
  2. The precise, musical, repeating nature of the sound
  3. That it has occurred on battery power at my girlfriend’s as well as in my house (plugged in).

Makes me wish there was an app like Little Snitch but for audio output instead of network traffic…

  • That's a really odd sound...
    – Austin
    Commented May 12, 2011 at 0:38
  • 3
    Pretty sure that "mysql" is the wrong tag. :) Commented May 12, 2011 at 3:56
  • 3
    @MatthewFrederick MY System's Queer Language?
    – ughoavgfhw
    Commented May 12, 2011 at 4:18
  • Did I tag it “mysql”? I tried to tag it “mystery” and gave up because that’s not a real tag; it must have auto-completed to “mysql” for me.
    – Alan H.
    Commented May 12, 2011 at 17:28
  • 1
    Wiretap studio DOES have application specific recording, and will record only the audio from that process. You could try the trial. Commented May 13, 2011 at 13:17

3 Answers 3


It’s the “Inactivity Sound,” called “Bass,” that Assistly plays by default when you haven’t been using it for a few hours.

And I thought my computer was overheating!

I can’t understand why anyone would make a web app that non-obviously plays a repeating, scary sound on repeat hours after the user last interacted with it.


Anyway, that’s one mystery solved.

You can +1 my relevant feedback to Assistly here.


Definitely computer-generated.


Melodic-range spectrogram

  • Off topic, but what program did you use for the FFTs?
    – Fake Name
    Commented May 12, 2011 at 5:26
  • 1
    @Fake Name Sonic Visualiser
    – ændrük
    Commented May 12, 2011 at 13:05

Sounds like a dashboard widget that is making sound when not in the dashboard, I have heard stuff like this from say an asteroids widget.

  • Good thought -- it does sound rather "game-like".
    – Austin
    Commented May 12, 2011 at 5:10
  • Not a bad guess at all, but my only dashboard widgets are iStat Nano & Apple’s default calendar widget.
    – Alan H.
    Commented May 12, 2011 at 17:28
  • Damn! I thought I had the magic answer :( Commented May 13, 2011 at 13:15

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