Equanimity training: “All these sounds that appear for ears that hear, Taken as agreeable or not, Let them rest in the realm of sound and emptiness. Past all thought, beyond imagination, Sounds are empty, unarisen and unceasing...” https://youtu.be/v-Su1YXQYek
Part 2: http://youtu.be/RpAFPAKQtj4 NB: ‘Trigger practice’ - small hits of deliberately chosen stimuli, used in order to push the envelope of concentration, sensory clarity, and equanimity, ie: attention. Rather than forcing effort, you can just gently manipulate setting.