I am using Audacity 2.1.2 on Windows 10. I have used Audacity for a long time, but only at its most simple levels. I have never really edited an audio file besides cropping it and speeding it up. I am new to the forums and just registered today although I have lurked for years.
My current main usage for Audacity is to record myself while I talk to a friend on Skype, I use this captured audio to create an m4a file of my voice which I send to my friend. He uses this with what he records of his voice and we make a simple podcast. I use a headset with mic attached to record and I have been picking up the person I talk to on Skype recently. What setting can I use to ensure I am capturing only my audio, or is it a matter of using an independent microphone separate from the speaker unit?
Second, and my most important pressing question, I have the raw audacity project of what I recorded, about 30 minutes of very soft audio of my friend abbreviated with my talking intervals which are of normal loud volume. Is there anything I can do with this file that I have now to separate out his very soft low audio out of the file, leaving behind the louder portions that are just me; with basically silence when he is just talking?
I found this, am I on to the right thing?
http://manual.audacityteam.org/man/tutorial_vocal_removal_and_isolation.html
Here are the raw audacity projects if anyone wants to look at them to help or just know what I am trying to explain. It is a part one and a part two with the corresponding directories that audacity created for each project. Basically it is just the first half the show and then the second half.
https://drive.google.com/open?id=0B7uF7o7YRQgmY0d4NmVBTThyRGc
Thanks for any help anyone can provide or any links that would help! We have done a few shows before this and Audacity either did not pick up his audio on my end in previous shows or he was just so soft that it did not matter. However for this recent show, he is far too loud for him to work with joining the file with his audio in Garageband. 
Doing a split recording like that is a good idea. I shot a branch of a broadcast show like that once. Once you get past the individual studio problems, you should be good to go.
Chances are good, however, if you have sound problems, it’s because Skype wants it that way.
Skype can be vicious about its own pathways and settings. In general, people have trouble when they try to do two different sound jobs at the same time and I’m not shocked it doesn’t work right.
Again, in general, we recommend software that “knows” what Skype is such as Pamela. I personally did it with two computers, the sound machine and the Skype machine. The sound machine doesn’t have to be a computer. Anything that will record your voice should work. You do need the headphones…
Koz
You could have hardware problems. Is this the same machine you use to record YouTube or other on-line sound tracks? Those settings will profoundly affect the sound quality.
You are experiencing both ends of product development. You are using Skype for this job precisely because you know Skype is going to connect correctly and establish a clear, reliable conversation pretty much no matter what. They do that by taking over your computer. Skype works no matter how screwed up your computer is.
The down side of that reliability is no options. There are only two known ways to reliably do production with Skype: Use a software package that knows what Skype is such as Pamela Professional or Pamela Business. Both of those will provide a split stereo sound file with you on one side the the guest on the other. Getting from there to what you want is a snap.
http://www.pamela.biz/en/products/
Other people make Skype capture software.
https://forum.audacityteam.org/t/help-recording-with-a-mic-laptop-and-headphones/35068/6
The other way is two computers. that’s how I did it.
And that’s how most “grownup” productions do it. This is a scene from Pando Podcast.
All that and it’s still possible you have your microphone set up wrong. Look at the Audacity Device Toolbar and make sure you’re recording from your microphone specifically and nothing else. It’s also possible to get your local microphone set up and Skype will stop working.
Isn’t this fun?
Koz
Missed a step.
There’s no good way to get from a mixed performance back into the individual voices, instruments or sounds. So no, we can’t split one voice off and delete it.
You would think since one voice is lower volume than the other, there should be some tool. There is. It’s called a noise gate, but you rapidly find it almost impossible to produce a theatrically pleasing show after hacking it up with a gate—if you can get it to work at all.
http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Noise_Gate
Koz