Sound Studio 4 – Mac App for Audio Editing
[REF]:
https://www.felttip.com/ss/index.html
[Stereo to mono convert] Record, edit, and produce your audio with Sound Studio, an easy-to-use Mac app for recording and editing digital audio on your computer. Digitize tapes and vinyl records, record live performances, create your own mixes with crossfades, tweak the levels and EQ, apply digital effects and save in all major file formats.