Sound Siphon is described as 'Software package that makes your Mac’s audio output available as an audio input device. It enables you to send audio from one application to another where it can be processed, streamed, or recorded' and is a Audio Recorder in the audio & music category. There are more than 10 alternatives to Sound Siphon for Mac, Windows, Linux and BSD. The best Sound Siphon alternative is Audio Hijack. It's not free, so if you're looking for a free alternative, you could try JACK Audio Connection Kit or BlackHole Audio Loopback Driver. Other great apps like Sound Siphon are Soundflower, Virtual Audio Cable, Loopback and SoundDesk.
easiest and free solution. In mac os settings, set imput and output to Blackhole (virtual device) and use any program like Audacity to rec the audio!