I have been on a spiritual quest for a few years, now. One of my practices is making immersive environmental audio background tracks, with embedded brainwave entrainment, and listening throughout the night, using a Bluetooth sleep mask. Using this method, I have freed myself from my PTSD unwanted thoughts and calmed my emotions. I have also noted that the soundtrack will sometimes appear in my dreams. For about two weeks I have experimented with 90-minute meditation tracks with low-Delta to Theta brainwave entrainment. This has triggered a long lucid interval. I am now creating more sessions for experimentation, using different lucidity cues when at the Theta level. If anyone's interested I will post the results.