Here is an interesting way to practice double octave scales in all the major keys. In "double octaves", each hand is playing an octave, and the thumbs are an octave apart. You'll need all 88 keys; in fact, the A-flat scale really needs 89.
Start on the lowest C. Play an ascending C Major scale in 8 triplet beats, ending on F. Without pause, maintaining the same tempo but with four notes per beat instead of six, reverse direction and play the descending C Major scale from the top F, ending back on the original C.
On the way up, hold the sostenuto pedal on the first note of every other beat, starting with the initial C. The sustained notes form a legato descending scale of C, B, A, G, F. On the way down, hold the sostenuto pedal on the first note of every beat, forming a descending circle of fifths on F, B, E, A, D, G, C. Hold the final C for one beat, then play another triplet beat consisting of D, E, F#, and end on (the lowest) G. (If you don't have a sostenuto pedal, hold the sustain pedal for a half-beat instead.)
Continuing immediately from G, play up and down the G Major scale as you just did in C. After holding the final low G for one beat, play another triplet beat consisting of G, F#, E, and end on (the lowest) D.
Repeat for each scale until you come back to C. As you make the transition to each new scale, always use the descending segue if possible so each scale begins on the lowest possible octave.
I wrote software that plays this exercise and saves it as a MIDI file, which I converted to the audio that you can play above.
In the first version of the software, all the notes were equal intensity, and of course, it sounded robotic. Even an exercise has to be played with some expression to sound human. It turns out that we humans subconsciously like to hear notes grouped into small units, with different intensities on each inner note within a group. The approximate intensities of the notes in each group of 6 is 100 60 65 66 64 66, and each in group of 4 it is 100 64 66 64.
David Arthur Yost, Yost.com, All Rights Reserved.
Sheet music, MIDI file, QuickTime movie, and other media realizations of these instructions are also copyrighted by this author. Permission required for republication in any form.