Binaural beats Delta Sleep Track
The only sound that I use on the sleepbuds is the white noise track. The other sounds, to me, don't make sense due to the variation of sound waves that don't work for sleep.
One track that would be very useful is a delta wave Binaural beats track with, which corresponds to the brain state of sleep.
See example here although ideally I would prefer a deeper bass sound:
I think this would really add value to the Sleepbuds as it is well known binaural beats entrain the brain for better sleep (as well as other states e.g. gamma for concentration).