Can someone explain when the 3rd valve slide should be used? I know it is used to bring certain notes into tune. Does every trumpet have notes that need this compensation? Should one make a habit of using that slide, or is it possible to get by without it? Someone teach me everything I need to know about that particular tuning slide. And while we're at it, if a horn is equiped with a 1st valve slide triger does it take the place of the 3rd valve tuning slide, or are both engaged?