I don't know how the original problem was solved...
Originally Posted by Krysstofur
One thing I know from my own experience -- USB audio is flakey on the iMac.
Check in System Preferences, Select Sound - make certain that the input and output values are selected to be your headset.
Note that your headset will only show up in this panel when it is plugged in... and that it can take a couple of minutes for it to be recognized by the iMac.
I use a powered hub which "should work" -- sometimes it does, sometimes it doesn't. Plugging directly into the back of the iMac does make a difference.
Another tool which can be used: Applications/Utilities -- Audio MIDI Setup.app
The other "trick" I use is to plugin and configure my headset BEFORE I launch LOTRO.
However, the real winning trick -- Use Mumble
27 inch iMac Intel (mid 2010)
Processor: 2.93 GHz Intel Core i7
Memory: 8 GB 1333 MHz DDR3
Graphics: ATI Radeon HD 5750 1024 MB
Display: 27-inch (2560 x 1440)
Software OS X 10.9.2 (13C64)
Audio FX 5+1 USB headset
Bill Magill - Mac Player - Old Timers Guild- Gladden:
Valamar: Dwarf Hunter - Level 105
Valdicta: Dwarf Rune-keeper - Level 105
Valanne: Beorning - Level 91