I noticed that in the map railyard, when your in the hall of the depot... the firing sounds ecco much more. Is this a paritcular setting during map building or just in game?

This is in-game code. No setting during creation of the map.

You can set an entity the determine the enviroment used.

I'm not shure it's in the source maps we released though. The entity's name is target_env and it let's you pick the reverb type, which are two mono sound files btw, and the pick a stereo ambience in addition to anything you place with standard target_speaker entities. I'll try to find out the exact syntax for you, but you're well advised to wait for our next update, when everything jumps to 44kHz.

The stereo ambiences and stereo reverbs need to be stashed as two mono WAV files. For example, in your target_env enitity you may say that your stereo ambience is called "sound/amb/roomtone". This means your files have to be named "sound/amb/roomtone_1.wav" and "sound/amb/roomtone_2.wav".

The enviroment entity closest to the player is used. We're still tuning the crossover time though, for when you move from one enviroment to the next.

The naming sheme is the same for reverbs. Just take a look in sound/reverb of the pak2.pk3 to listen to them.

Wow I stand corrected. Sorry mates. This game engine is really cool.

it's basicaly a shader trick..

the echo effect works if you can trick the player entitiy into thinking it's outside.

basicaly your adding a shader brush that tells the map that the player entitiy is outside even though you built an indoor structure around the brush the entitiy will read it like a skybox and use the echo effect.

I haven't tried it but it might cause a problem if you use rain or snow though .