I couldn't get my Real Player to play the spectrograph illustrations. It kept on buffering...

awaddle, sounds like a good ol' dodgy connection to me! There's a novelty.

Now, you should be able to download the entire sound file(s) rather than play them as a live and shaky audio stream.

If you have Internet Explorer, right-click on the spectrographs/sound files and select Save Target As... then choose a location and filename on your PC.
The files may take a little while to download, but sounds to me like the wait would be worthwhile for you.
One they're downloaded, just double-clicking on the local copies should play them.

So go for it, and enjoy!

I can probably suss how to do this on other browsers if you don't have IE. Keep us 'posted'.