Download and install Ecamm
To download Ecamm for Skype calls, click here.
Install the app. Once you are done with the installation, you will see the following menu.
Make sure to select record audio only and enable recording automatically. You may also change where your files will be saved if you like.
You are now able to record your Skype calls. When you make a call, you will be able to see this small window.
Reducing the file size to 32kbps
When you click on the magnifier icon on the Ecamm window, this window will pop up and it will allow you to edit your recorded file. Select Good Quality in the setting to shrink the file size. This turns your recorded file to 32kbps.