I am using a digital recorder to record professors' lectures for my classes. After loading the .mp3 files on my PC, I found out that in most cases, the back ground noises seriously interfered with the professors' voices ( the humming noise usually heard in recording ) _ Is there a way to reduce these noises ? _What is the best Audio editor would you recommend for this job ? _ Is ther such a program that just pick out the human voice ? Please comment . Thanks .