While not exactly a device, music is usually delivered electronically these days. There is no question it can put you in the right frame of mind and—equally important—take your mind off distractions.
Slow and relaxed is best. Slow baroque music is famous for changing mental states favorably. At all costs, avoid heavy clashing pop music. With its disagreeable rhythms and often-times nasty lyrics, you’ll never fall asleep listening to that (tested fact).
I won’t be providing you with a playlist; that’s up to you and your tastes. But I will share the science of what works well and what doesn’t and even some example tracks of what to look for.
One other bonus: it can easily drown out background noise that may be troubling. However, we do NOT want loud sleep music. That’s rather counter-productive.
It’s hard to resist the sleep-inducing properties of sounds such as these. I have recorded creative meditation tracks which some people cannot get to the end of… they fall fast asleep before the ends.