With PPT 2003 if you right click the speaker icon and go to EDIT SOUND OBJECT you get this dialog.

In PPT 2007, click the speaker icon and the ribbon goes to the SOUND TOOLS ribbon. It gives you a lot of information.

Of note the MAX SOUND FILE SIZE (KB) is now not a hidden dialog (be sure this is set to 50,000). But where is the embedded/contained information?

You need to click the more info button in the lower right corner to bring up the legacy dialog to see information about it your audio file is linked or embedded (contained).

– Troy @ TLC