• Help with pitching starting notes for the exercises: Various online pitch pipes are available that will play individual notes to help you to choose suitable ones, and then replay them on demand. For example: www.harmonize.com/metropolis/online_pitch_pipe.htm and the free Android app Pitch Perfect. Alternatively, there are a variety of apps that give you digital piano keyboards.

• What the diaphragm does during diaphragmatic breathing: On the in-breath of diaphragmatic breathing the diaphragm contracts (tightens) and moves downwards, increasing the size of the chest cavity. This lowers the pressure in the cavity, which in turn allows fresh air to be drawn into the lungs. On the out-breath the diaphragm relaxes and moves upwards, raising the pressure in the chest cavity and thus automatically expelling stale air from the lungs. This video shows (in exaggerated form) these movements of the diaphragm, and also how the associated movement of the ribs helps the expansion and contraction of the chest cavity:

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• Nasal breathing: Breathing through your nose rather than your mouth has significant health benefits, as Patrick McKeown explains in his TEDx Talk (16 minutes) ‘Shut your mouth, change your life’.