I realize this is more than 6 months old, but I think I have a solution. And I know I appreciate it when someone presents a simple solution that doesn't involve a bunch of terminal commands, etc. LOL
This worked for me, anyway.
Open synaptic package manager.
Type in "pulseaudio" without the quotation marks, and run together into one word like that. (Doesn't work, if you separate it into two words.) Let the program come up with a list.
Now install or reinstall everything that is even remotely pulseaudio. (Don't bother to uninstall so you can reinstall. Just reinstall.)
Once that has finished...
Right click on the bottom taskbar and choose to add to it.
Choose the indicator applet. Just the plain one. That should give you back the speaker icon. It includes the connection information icon. If you still have the connection icon on your taskbar, you can just remove the old one. I have no idea how to remove that icon from the new indicator applet.
I hope this works for some one.
I was following all the instructions in this thread and at least a dozen others here, trying to fix this problem.
Nothing worked. Apparently because some part of pulseaudio was not installed, or was not installed properly. Doing the reinstall, made the icon show up again, in a new indicator applet.
Before, the icon was nowhere to be found. Install applets all day, and it wouldn't be there.
And the icon didn't just show up in the old applet. I had to add a new applet.
"The true measure of a man is how he treats someone who can do him absolutely no good." ~Samuel Johnson (1709-1784)