Audio Interfaces and Mixers are the two completely different things in the gears for music production for your home studio. The audio interfaces are basically DSP. DSP stands for Digital Signal Processors. The work of the audio interface is to convert the analog audio signals into digital audio of any instrument or vocals. Whereas if we talk about mixers, that combine various audio channels into a single channel. It might be equipped with other functions as well, like phantom power or equalizer, etc.