Let's say you have an interview-format podcast with a guest who connects via phone or Skype. Or you have a co-hosted podcast with a co-host who connects via phone or Skype. To record this podcast, you need to get both sides of the conversation on tape. But "both sides of the conversation" is a problem for the guy connecting via phone or Skype. He only needs to hear your side, because sending his part of the conversation back to him will come through an echo and is a potential source of…