don't put your gate on the master. The only reason I would see for doing this is to cut off the hiss before and after the track is done playing. All you would be doing is possibly cutting off parts of your actual beat. Maybe it gives a certain effect but it seems like you wouldnt want that. Gates are used to cut off unwanted background noise so i'm not sure what it'd do for you on your master buss. My .02,
Peace!!