He demonstrates how he mixes one of the songs he wrote for MapleStory: Taiwan Night Market with original instrument tracks. He wrote, mixed and mastered this song. Though he speaks in Korean, you know, music guyz, or those who have experienced any DAW and in-box plug-ins, you can understand what he shows by just looking what he clicks and adjusts in the DAW window. (He is using Cubase 9 here) There are Two parts of it: Part 1. Part 2. It is pretty funny, in the beginning of part 1, when he plays the official version of the song used in game, he says actually now he hates, regrets, and is ashamed of how he mixed the song in the past, because there's almost no bass, no low frequency in the mix.
