Update gain information

Author: devoxin

IMPLEMENTATION.md

@@ -124,7 +124,9 @@ Using the player equalizer
 }
 ```
 There are 16 bands (0-15) that can be changed.
-`gain` must be a float between -0.25 and 1.0, where 0.0 indicates no change.
+`gain` is the multiplier for the given band. The default value is 0. Valid values range from -0.25 to 1.0,
+where -0.25 means the given band is completely muted, and 0.25 means it is doubled. Modifying the gain could
+also change the volume of the output.
 
 Tell the server to potentially disconnect from the voice server and potentially remove the player with all its data.
 This is useful if you want to move to a new node for a voice connection. Calling this op does not affect voice state,