For sleep, the qualities of the music matter more than any specific track or frequency. Slow, quiet, low-stimulation sound tends to help most: a gentle tempo, few or no lyrics competing for your attention, soft dynamics with no sudden changes, and a predictable, unsurprising texture. Music like this works as a cue that the day is over and it is safe to wind down. There is no single “best” song and no proven magic frequency for sleep; the honest guidance is to choose calm, steady, familiar sound and keep it consistent.
A racing mind at night is common and usually not a sign that anything is wrong. When the body finally goes still, the mind can get louder. A few gentle, non-medical things tend to help: giving your attention something calm and undemanding to rest on (like slow music or the feeling of a long exhale), slowing your breathing so the out-breath is longer than the in-breath, and keeping a screen-free wind-down so your mind is not being pulled awake. None of this is a cure for insomnia, and if sleeplessness is persistent it is worth speaking to a professional. But as a nightly ritual, calm sound and a slower breath can make settling easier.
Practical notes
Keep the volume low, decide in advance whether the audio loops all night or fades out, and let the routine be repeatable so it becomes a familiar signal rather than a one-off. If you would like a ready-made calm wind-down you can return to each night, the 21 Day Reset is built as a short daily practice, and many people use it before sleep.