Prolonging the Fundamental Structure (cont.)
Prolongations of the Fundamental Structure (Register Transfer)
Like the mixture, register transfer is an embellishment rather than a diminution. In the foreground register transfer often just adds colour, particularly in piano textures.
In the first level middleground, any notes from the fundamental structure or their neighbour notes can be transferred up or down an octave. The most easily recognised example is when a melody is played and then repeated an octave higher but register transfer can be much more subtle than this.
Whatever register transfers may occur, the fundamental descent must still take place in the obligatory register.