I love working on the sound related stuff for my game. I cannot wait to play more with the HRTF library I've purchased a license for. It's mindblowing how accurately you can locate sounds with it.
I've been working on footstep sounds during the past couple days and I'm almost done with them.
v1:
-Footstep sounds played in sync with subtle(!) headbob so it's authentic
-4 different footstep sounds plus one for jumping and one for landing
-Played from an audio source located right at the player
v2:
-Different "Sound sets" (4 step + 1 jump + 1 land + loudness-factor) for different floor-types
-Factor will be used to determine the range at which enemies can hear you (think about Thief)
v3:
-Use code generation to generate a dictionary that manages all sound sets offline, so you need no extra calculations during the game's runtime (performance)
-Use two audio sources located at the player with tweaked stereo panning so you have a sublte difference between your left and right foot
Todo:
-Make subtle changes to volume and pitch depending on the movement speed of the player.
-Make using ladders override the sounds temporarily
The next thing to tackle will be creating an ambient sound system for Unity, that is inspired by the "Soundscapes" for the Source engine. What I want:
-play different variations of the same ambient sound so you don't get obvious looping
-memory so it doesn't play same one twice
-randomly play additional sounds (birds, insects, thunder, etc.)
-support for spatial environment sounds with and without HRTF
-crossfading between various environments
Implementing this will be tons of fun.