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3460169

Cancelled
Original poster
Feb 18, 2009
1,293
212
Before I continue -- yes -- the solution is just to ****ing crank the volume! And listening to Anterior's latest offering at the moment rest assured that is exactly what I am doing! lol Regardless, for the rare but necessary quiet times it'd be great if this MBA didn't buzz through the 'phones.

  • 2011 13" MBA with Lion 10.7.1
  • Sennheiser PXC 450 noise-cancelling headphones (in normal mode with NoiseGuard activated, i.e. noise-cancelling turned on). (I have some Buy Other Sound Equipment QC15 'phones as well, but not with me currently and can't test)
  • MBA charger plugged in

With the MBA charging and the headphones turned on but no sound playing -- and when not touching anything on the MBA -- there's a good amount of buzzing. The buzzing ceases if I do any of the following:

  • I touch (and thus ground) the MBA
  • I put the headphones into bypass mode (so they act as "regular" headphones); presumably any other "regular" headphones wouldn't exhibit buzzing either
  • Unplug the MBA from the charger
  • Crank the tunes!!!! ;)

So it's some issue with the active nature of the headphone's noise-cancelling features, possibly combined with a bad ground of the headphones and/or MBA? I'd love to hear back from other 2011 MBA users with NC headphones.

Thanks,
f00f
 
To rule out the headphones I tried them in a 2010 21" iMac and a 2011 MBP (that was charging) with no discernible buzz. Have to try those QC15s later but have a feeling the Air will be to blame.
 
I have a set of Sennheiser NC BT headphones (MM-550), and I should receive my new MBA in 7 days time. I'll try and test this issue, and report back :)
 
I have a set of Sennheiser NC BT headphones (MM-550), and I should receive my new MBA in 7 days time. I'll try and test this issue, and report back :)

OK that'd be great, thanks! :)

Right now it seems like a fault ground, just a question of where, and I can't get a better idea till I'm not at work.
 
Problem solved.

While I knew with near 100% certainty it was a grounding problem, I never thought to question whether my MBA's MagSafe was indeed grounded.

Well, unless it's used with the 3-pronged extension, it isn't grounded properly -- and I had been using it without said extension (it's at home). I just borrowed my co-worker's MagSafe extension & the buzz problem is gone.

Thanks to "Mario" at the Apple discussion forums for this insight.
 
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