I’ve been adding sound to my animations using Cinelerra and Avidemux. These two apps together work like a charm.
I compose sound fx and music or anything in Cinelerra (using a TGA sequence from Blender) to synchronize, then render the audio only and multiplexing it with Avidemux (which reads aviraw and divx too) and encode the whole package as avi.
Just in case you’re a linux monkey !
Hope it helps.