With Wavelab, I look at the spectrum during playback, and usually the highest of the mid frequencies are what I lower to get rid of the echo, but it really is trial and error. I dig using wavelab because I can just open up a Q-10 equalizer and tweak with it WHILE it is playing back, so that I get on-the-fly feedback. The frequency ranges already stated are around the ones that I usually end up reducing as well, FWIW...