Main differences between embedded (embedded object: Information (object) contained in a source file and inserted into a destination file. Once embedded, the object becomes part of the destination file. Changes you make to the embedded object are reflected in the destination file.) sounds (objects) (object: A table, chart, graphic, equation, or other form of information. Objects created in one application, for example spreadsheets, and linked or embedded in another application are OLE objects.) and linked (linked object: An object that is created in a source file and inserted into a destination file, while maintaining a connection between the two files. The linked object in the destination file can be updated when the source file is updated.) sounds are where they are stored and how you update them after you put them in your presentation. Embedded files are stored within the presentation, and linked files are stored outside the presentation.
For more details visit:
http://powerpointinfo.blogspot.com/2009/06/embedding-or-linking-audio-file-in.html