I had an echo in some of my previous Podcasts I couldn't figure out where it was coming from, until a kind person - Daxy Perez suggested to me to check my reverb. What is a reverb? Turns out in Garage Band (which is where I edit my podcasts) has a setting I must have accidentally clicked onto give me an 'echo-y' voice for many of the podcasts. I've corrected it! Thanks Daxy for your suggestion. :o)