Soft, gradual sounds like birdsong, rainfall, or rising chimes are top performers for a stress-free transition. These sounds provide a "gentle escort" into wakefulness.
Choosing the right sound depends on how your brain responds to auditory cues during sleep. Scientific consensus favors tones within a , as these are easier for the brain to detect without causing a sudden shock.
What Science Says About the Best Alarm Sounds for Waking Up | Mudita