Crisp is best for competitive matches because it emphasizes the mids, which helps you hear gunshots and footsteps better, and that's very important in terms of audio settings in CS2. And Natural is the median version, basically the point right between the other two options.

Yep, its because of the forced 3D sound processing. Tries to mimic surround sound, which on most audio devices (yes even extremely expensive equipment) tends to sound terrible.

Microphone Settings in CS2 Depending on the position of the sound source relative to the player, you hear it differently. Perspective correction should help more accurately determine the direction of the sound source. So, if you want to keep the sounds the same as they were in CS:GO, disable this parameter.