Apple has released LED Cinema Display Software Update 1.1 which addresses an issue with the 27-inch LED Cinema Display audio output.
Specifically LED Cinema Display Software Update 1.1 patches a bug that “may prevent sound from playing back through the speakers on the display,” Apple says.
Customers are instructed to leave their 27-inch LED Cinema Display attached to their Mac during the update process. According to a tech note on Apple Support describing the update, “Your screen may go black momentarily while the update is installing.”
Updated FW versions are MLB - 299 and Audio - 1.20, Apple says. The update applies to Mac OS X 10.8.2 Mountain Lion or later versions.
Supported languages include Deutsch, English, Français, Español, Italiano, Nederlands, Dansk, Norsk Bokmål, Polski, Português, Português Brasileiro, Pусский, Suomi, Svensk, Chinese, Japanese and Korean, according to the release notes.