Fixed Do Vs Moveable DoFixed Do helps young children (0-6) develop Absolute Pitch. Moveable Do is better saved for school-age kids (6+) Written by Mr. Rob Fixed Do helps young children develop Absolute Pitch. Moveable Do is better saved until school-age, when kids are less likely to develop AP but ready to develop Relative Pitch. One of the most common questions we get about Prodigies is about our choice to use Fixed Do instead of Moveable Do.