I won't go into it here, but trying to set up 'surround sound' through headphones, which always have only left and right drivers, is a bad idea in my opinion. The settings discussed here are in regards to playing CS:GO's sound in a simple stereo arrangement (headphones, 2.0 or 2.1 speakers). But since this is exactly what HRTF is for, and it does it way better, you don't want to use altered settings because they will only screw up the HRTF calculations the game does itself.

This is because I was suggesting ways without HRTF to manipulate the sound to try and give advantages for discerning left-to-right position and distance over the default settings.

For HRTF, you should actually use the default settings that I called non-recommended at the time.