This is the strangest setup of a conference call I have been in for a while: A Skype video session with high quality audio over speakers and a third person, also on the other end, part of the conversation over a mobile phone as part of the call via loudspeaker/hands-free mode. The person on the other end of the line didn't even realize I was not in the room but a thousand kilometers away. On my end, the speech quality of the hands-free mode on the other end was also pretty much the same as if the phone was on my end. Speaks for Skype's audio codec and the echo cancellation of all devices.