extract audio from Keynote (or PPT) file

I received a PowerPoint file in which someone had embedded an audio track. I needed to extract the track for the sake of using it within the presentation system that we use. I knew that it would be a resource within the package but the file is a single file.

solution

I opened the file within Keynote, changed the file type to Package (File > Advanced > Change File Type > Package), saved the file and then from within Finder chose Show Package Contents. The audio file(s) is within the Data folder.

Simple when you know how!