As far as I know, there is not. However there is a way you can reduce the size drastically.
I have a little trick I use. Download the free program Audacity from
http://audacity.sourceforge.net/
When you install and open it for the first time, open the sound file and play it. What I do is watch for when the sound waves are at a silence at the begining or end and highlight that section, and delete it. Alot of times the large amount of space comes from the static at the end of a sound file. Another thing is you can completely remove the left balance of the sound because you wont be able to distinguish from stereo or mono on a sound file
If you want, you can send the sound files or post them and I will optimize them for size without reducing the quality. If I get them within the hour, I may be able to get it done tonight, if not I'll try to do it for you in the morning