If you’ve got a new Intel-powered Mac, here’s a feature you may not have even known you had. For years, all Macs have had the ability to have different volume levels for different inputs. Plug in a USB-powered iMic, for instance, and you can set its output volume level independently of that of your internal speakers.
What never used to work, however, was setting a different volume level for a standard set of headphones plugged into your laptop’s headphone port. Even though the system would recognize the fact that you had plugged in a set of headphones (the display in the Output tab of the Sound System Preferences panel changes, for instance), any volume level changes you made were universal. Remove the headphones, and whatever setting changes you had made would remain, even though you were now using the internal speakers as the output device.
With the Intel-powered Macs, however, things have changed. The headphone jack is now seen as a “real” output source, so any volume settings you make with headphones connected are not retained when you unplug the headphones. This is a very nice change, as it allows you to easily have two distinct volume settings in action—one “with headphones” setting and another “without headphones” setting.
One possible use for this tidbit of knowledge is to create a muted “non-headphone” setting. Plug in a set of headphones, set the volume level to your preferred level, then unplug the headphones. Now mute the system sound by hitting F3 (or Fn and F3, if you have your machine so set). Until you plug in your headphones, your Mac will be silent to the world, letting you use it in the library without fearing everyone will hear your AOL-inspired “You’ve got mail!” new e-mail announcement. Plug in your headphones, though, and the previously-set level is restored, and mute mode is canceled. Rock out to John Denver and ABBA all you like, and when you’re done, unplug your headphones again. Bingo, your Mac is now once again muted.
Of course, you don’t have to have the non-headphone Mac muted. You can simply choose a different volume level—perhaps you have very efficient headphones, and you need them set at a quieter level than when using the built-in speakers. In short, on an Intel Mac, you can now use any volume setting you want for your headphones and your built-in output.