Comparing linked and embedded files.
To guarantee that a sound will play from the computer you present on, be aware of some details concerning the size of sound files, and whether a file has been linked to in the presentation, or embedded within it. Your main concern is that any files your presentation links to must be in a place where PowerPoint can find them.
A linked file is not actually contained within the presentation. Instead, PowerPoint creates a link to the file based on where it's stored when you insert it into the presentation. For example, it might be on your computer, or on a server that your computer is connected to. So when you "insert," you're really just creating a link to the file. PowerPoint relies on that link to find and play the sound.
The tricky thing is that if you move the sound file to a different place, so that the link to it isn’t valid anymore, or you present on a computer that doesn't have access to the sound file, PowerPoint won't find the sound file to play it.
The next screen tells you how to prevent this.
What determines whether a sound file is inserted as a linked file? File size and file type. PowerPoint creates a link for any .wav type of file that is more than 100 kilobytes (KB) in size and for all other types of sound files, regardless of size. (The last four characters of the file name — for example, ".wav" — tell you what type of sound file it is.)
An embedded file is part of the presentation. If you copy the presentation to another location, the embedded sound file travels with the presentation and you can count on it to play.
What determines whether PowerPoint embeds the file? Again, file type and file size. If the sound is a .wav file that is 100 KB or less in size, it's embedded.
Remember The presenting computer must have a sound card and speakers to play your sound effects.