SoundSource 2.0 is a little "MenuExtra" that provides instant access to Input, Output, System sound settings, volume settings, and a quick way to get to the full Sound Preference Pane. This is very nice for many reasons. I use my MacBook Air to control my Mac Pro through the screen sharing function in OS X. While it works extremely well I still find it cumbersome to access Audio Midi Setup to switch sample rates and select outputs. This frequently involves moving the iTunes window partially off the screen or making it very small in order to access the Audio Midi window I previously left open. If I don't leave Audio Midi open I have to access it through the Dock, which brings up a host of other little issues. For example the Docks on my MacBook Air and Mac Pro will appear simultaneously when I lower the mouse to the bottom of the screen. This may sound a little weird so I suggest trying the screen sharing function in OS X and you'll see what I mean. Yes, there are several ways around this little issue like shrinking the size of the screen sharing window, but I don't consider that an ideal solution.
SoundSource is actually just a little menu that appears in the upper right by the clock in OS X. This menu allows one click access to almost all the necessary functions you'll need when listening to your music server. When you need that one little option that you can't access via the menu, SoundSource provides a link to the full Sound or Audio Midi preferences pane. This allows me to remote control my Mac Pro and leave the iTunes window at full screen. I know it sounds like a complaint to have when one runs out of other items to complain about, but this really is an awesome little menu extra.
When I review equipment I frequently need to change outputs and sample rates to compare one product to another or one feature to another. Having this access with a single click is so nice. I can concentrate on the music instead of the software interface and the changes that need to be made. Again, it may sound petty, but don't knock it until you try it :-)
The ultimate feature would be selectable sample rates from this menu, but I guess we can't have it all for such a reasonable price.
The application is available free from Rogue Amoeba at http://rogueamoeba.com/freebies/
Here is some additional information from the SoundSource ReadMe:
This menu will vary based on your specific audio devices. To switch between them, simply select them in the menu, and all your audio will be routed through the chosen device. To adjust the volume on a device (Output, Input, and Alert volumes), simply move the appropriate slider.
You may also access the Sound Preference Pane quickly by choosing "Open Sound Prefs..." and the Audio MIDI Setup application by chooising "Open Audio MIDI Setup...".
If you install SoundSource for multiple users, the Installer will open it for the current user, but you'll need to "open" it for all other users manually. When logged in as a different user, go to /Library/Bundles and double-click the SoundSource.bundle file. The SoundSource menu will now appear in the menubar for that user.
Mac Pro Users
On Apple's Mac Pro machines, the line output device is no longer paired with the headphone output. This means that plugging in headphones doesn't automatically switch your output to the headphone jack on these machines, as it did with all previous Macs. Previously, you needed to manually change your output on the Mac Pro, but with SoundSource's "Auto-Switch To Headphones" option (only available on Mac Pros) turned on, your output will switch automatically.