guys the steps is probably just imagination, everything is reversed.

@Hajt I don't think I've got enough time do that atm, but I'll try.

@ uLtR4: The problem lies either with you or your drivers. I just tested the sound output.

When having the headset on normally and a bot walks up the sound output is directed so that it sounds like the bot is moving upwards (correct).

When having the headset reversed and the bot walks up the sound output is directed so that it sounds like the bot is moving downwards (incorrect).

Tested with a Sennheiser CX-215 and a Sennheiser RS 120-II (both using Realtek High definition Audio drivers)

Shooting sounds are also correct.

So its just your mind that let you think wrong?

I would say yes, but why do many other people have the same issue?

A little checkbox "Enable reserved sound output" in the sound options would make it okay for me.

Is it only occurs when you are using CS2D?
Do you have some kind of software like Realtek Manager Audio or something to check (or even change) sides?

Try to plug your headset into another jack. Maybe that one is wrong or you are using 5.1 or higher headset. May be also problem with some driver numbers for more people. Post motherboard manufactor and model and driver version.

turn off surround virtualization in driver settings, was an easy fix for me.