I always play octatonic when I see a diminished chord. Is that wrong?
When phrased properly – with the magnetic forces of harmony and taken into account, the octatonic scale is a good alternative. Its symmetric structure with alternating half and whole steps is its strength. It creates an independent sound. Unfortunately, the typical sound of its primary patterns has often led to ‘formula playing’. Use the octatonic scale when it serves an expressive purpose, but make sure that you have the diatonic approach of diminished chords in your toolbox as well. Try to avoid formula playing like “I always do this when I see that”.
