OS 10.5: Why can I hear my headset's microphone now?

December 6, 2007 10:55 PM

Mac OS X 10.5 dumps the microphone feed of my headset into my ears; can I shut it off?

I use a Koss SD-35 headset and a "SPEED-LINK UltraPortable" USB Soundcard to Skype and what-not on my Aluminum 15" Powerbook G4 (1.25GHz).

This worked just fine in 10.4, but when I upgraded to Leopard, suddenly I can hear myself breathe, even when I'm not Skyping (and suddenly I get a low hum whenever I'm not touching the metal case of my powerbook - what's THAT about?). I realize that monitoring my mic input is a nice feature to have, but can I turn it off?

posted by anonymoose to computers & internet (8 comments total)

What do you see for this device in System Preferences -> Sound -> Input ?
posted by ikkyu2 at 2:27 AM on December 7, 2007

Is your Powerbook connected to earth? It isn't if you're using the small plug for the power adapter instead of the power cable.
posted by stereo at 7:27 AM on December 7, 2007

Powerbook is not grounded, no. Good call.

device shows up as C-Media USB Headphone Set, of type USB
posted by anonymoose at 1:22 PM on December 7, 2007

I take that back, powerbook *is* grounded, I think, assuming my cheapie 220V powerstrip with 110V adapters is allowing it; the strip does seem to have metal leads connecting to the ground wire, but I'll experiment with that.
posted by anonymoose at 1:25 PM on December 7, 2007

Do you have an option to adjust the input level in that pref pane, anonymoose? If you do, just drag the slider all the way to the left, that ought to shut the mic off effectively.
posted by ikkyu2 at 5:14 PM on December 7, 2007

You might also run Applications -> Utilities -> Audio MIDI setup.app

and check out the Audio Settings for the C-Media USB Headphone Set. These look different depending on the device, but you may find that the mic input is routed back out the headphones and you can disable that in this panel.
posted by ikkyu2 at 5:16 PM on December 7, 2007

You don't need a 110V-220V converter for Powerbook adapters. Try plugging it directly into the wall socket with a socket adapter.
posted by stereo at 9:53 AM on December 8, 2007

ikkyu2: Nice, you win :) stereo: It's just a powerstrip full of socket adapters; it's still feeding 220V.
posted by anonymoose at 2:20 AM on December 9, 2007