diff -r 927e1bca4bb6 -r 24c6057b2fda plugins/include/sdktools_sound.inc
--- a/plugins/include/sdktools_sound.inc	Sat Sep 03 14:11:38 2011 -0400
+++ b/plugins/include/sdktools_sound.inc	Sat Sep 03 14:18:08 2011 -0400
@@ -257,6 +257,15 @@
 				 bool:updatePos = true,
 				 Float:soundtime = 0.0,
 				 any:...);
+				 
+/**
+ *Calculates gain of sound on given distance with given sound level in decibel
+ *
+ * @param soundlevel	decibel of sound, like SNDLEVEL_NORMAL or integer value
+ * @param distance	distance of sound to calculate, not meter or feet, but Source Engine`s normal Coordinate unit
+ * @return			gain of sound. you can multiply this with original sound`s volume to calculate volume on given distance
+ */
+native Float:GetDistGainFromSoundLevel(soundlevel, Float:distance);
 
 /**
  * Called when an ambient sound is about to be emitted to one or more clients.