Basically, your computer represents sound digitally, and your headphones/speakers represent sound with analog signals. The schiit modi converts your digital music files into a line level analog signal.
There's a built in dac in every digital device that has a headphone output, including your computer, phone, and Hiby mp3. Most of these dacs are low quality (With the exception of the one in your mp3, it's probably pretty good), which is why...
