Mixing in mono means a music producer will flatten the songs mix into one single audio stream.
What You Will Need to Follow This Tutorial Let’s take a deeper look at what mono is, why it’s important, why you want to mix in it, and how it helps create polished, professional-sounding songs. This is referred to as mono compatibility.
A crucial step in proper mixing is making the mix sounds just as great in mono as when separated across the stereo field. One of the critical steps in producing a great, professionally sounding song is mixing and mastering. 6.7 What Is the Difference Between Mono and Stereo? Mixing In Mono