Ambient Sounds:


Here's how I did it;

Place a ambient_generic entity near the thing you want to 
make sound.  Right click on it and go to properties. In 
the PATH dialog box put in ambience/filename.wav 
(eg. ambience/sparks.wav) Notice that it is a FORWARD SLASH! 
Next set the VOLUME, 10 is loudest I used 7 and seemed about 
right.  Set the START VOLUME to the same value (7) the next 
boxes are up to you to experiment with, I left them alone. 
The last area I changed was FLAGS tab, check medium radius 
for an area of about 15-20 feet of sound range (at 7 volume) 
The main thing I found was that it isn't necessary to put  
sound/ in the PATH, that the .wav needs to be there and to 
use FORWARD SLASHES in the path name.

To look at the sounds available I used QPed (a Quake utility) 
and looked at the Sierra\half-life\valve\pak0.pak file.  If you 
use sounds in the other sub diectories of the pak file you must 
define it in the PATH.

Nailer
http://www.pyramid.net/steveg/index.html