currently i'm taking some classes where the teachers talk very fast, so i bought a digital voice recorder (the Sony ICD-U50). the recorder allows me to download the recorded sound files to my computer under the .DVF format. since itunes and no other audio player on the Mac can play this format, i use this program called Switch Sound (http://www.nch.com.au/switch/plus.html) to convert them to .MP3 format so that i'll be able to transfer them to my iPod. everything is fine except that, there are so much echos and noises, so i need to somehow improve the teachers' voice and reduce those echos and noises. and, of course, finally export to .MP3 format. it would be even greater if it could read .DVF format. can you guys recommend me some program to do that job? (i know absolutely nothing about digital audio editing, but i can learn) thanks in advance!