Unquestionably, the fundamental obstacle to developing strength in contemplation is relentless distraction from internal chatter, daydreams, and/ or external sounds and movement. In the following recommended recordings, music is the object of concentration. In this playlist, however, the music and sounds are the primary focus. In some, the artists have deliberately applied entrainment theory to their musical compositions, which means they use binaural sounds (different tones in each ear) to create the illusion of a beat at carefully calibrated frequencies. Listeners are meant to focus their attention solely and directly on the sounds of the track itself.