In Camtasia 2 for Mac, when I apply Noise Reduction, it will sometimes make the audio narration sound like its in a box, and very bass heavy. Others, it works perfectly. I've even had it where it's fine when I first apply it, then it will start to do the bass/boxy sound again. I'll have to quit and restart it. Currently I can't get it to work correctly at all and it's only making the narration sound terrible. I've troubleshooted this to death and I believe this to just be a bug.