Back on the Mac - Restoring Volume Defaults after upgrading to OS X Yosemite ( Sam )

Thanks to these two posts: -

Can you change the new Yosemite volume indicator sound?

Replace the volume changing sound

I now have the "old" blobby-clicky sound when I increase/decrease the volume on OS X Yosemite.

In essence, the first link includes a .AIFF file with which one replaces the default ( and new ) sounds, setting it back to pre-Yosemite.

In addition, it also shows one how to change the System Preferences to ensure that the sound is heard when pressing [Volume Up] and [Volume Down], rather than the ( now default ) shifted versions of those keys.

It's all good.