What causes notes to be flat below the staff? I tend to be flat on notes below B natural below the staff. This includes F# that should require me to kick out me third valve slide. Even on F# I am either right on pitch or slightly flat even with the slide pulled all of the way in. Notes in and above the staff are in tune. I used to have a problem with being sharp above the staff but am having far less trouble as I learn to relax more. One thing I have noticed that helps with getting the notes in tune below the staff is to play the same note 1 or 2 octaves higher, then play the note below the staff while trying to hear it in the higher octave. It will usually play in tune at that point. My question is what are mechanics behind playing flat below the staff. Is there a better way to improve this than what I am doing with trying to hear it up an octave?