Practice alternating between D in the low register and D in the middle register as shown in the following example. All you need to do is move your thumb on and off the octave key.
The following example contains the note D in both the low and middle registers. When using the octave key, try to keep the tone as even as possible between registers.
Up to this point, all of the notes you have learned have been in the low register of the saxophone, except for the note D in the middle register which you have just learned. This D note is exactly one octave above the low D.
You can also use the octave key to create higher versions of all the other notes you have learned. For example, if you finger an E note and add the octave key, this produces an E in the middle register which is exactly one octave above the lower E.
Once you are comfortable using the octave key to play the notes D and E in the middle register, try using the octave key with the note F, then G, then with all of the other notes you know. To play the higher version of each note, all you have to do is maintain the fingering and add the octave key.
The following three examples use the notes D, E, F, G and A in the middle register along with other notes you already know. The next example alternates between notes in the low register and notes in the middle register. Take it slowly at first.
Middle register notes using the octave key
To become familiar with the new notes, say the names of them to yourself as you watch the written music.