The auto note direction button cycles through the three types of Auto Note Switching. They are "Auto Up", "Auto Down", and "Auto Both". The current type of auto note switching is shown in the button itself. In all three cases, the software will only switch up to 300 cents (three notes) away from the current note. The three types of Auto Note Switching determine if the new note is allowed to be above, below, or on either side of the current note. If you are tuning chromatically from the low bass to the high treble, the normal setting is "Auto Up". In this way you can make aural checks on notes you have already tuned without worrying about Auto Note Switching following you down the scale as you make these checks.