Why Rain Sounds Work, and Why Recorded Rain Eventually Doesn't
Short answer: Rain is steady overall and random in every detail, so there is nothing to follow and nothing sudden. A recording is one stretch of that randomness played again and again. After enough passes you recognise a gust or a drip, and from then on you are waiting for it.
What rain has going for it
Three things. It is steady, so it covers the small noises that would otherwise make you look up. It is random in the details, so there is no pattern to learn. And it carries no meaning: no words, no tune, nothing that wants an answer.
There is research on natural sound in general. A 2021 review in PNAS went through studies of people listening to nature and found lower stress, better mood and better results on mental tasks. Water sounds had the strongest effect on mood and health. That is about natural sound as a whole, not about rain apps, but it fits what most people say about rain.
How a recording gives itself away
A recording is finite. Somewhere it ends and starts again, and somewhere in it there is a landmark: a heavier gust, a car passing, a drip with a particular rhythm. The first few times you don't notice. Then one day you do, and after that you can't stop. You catch yourself waiting for the drip.
Short loops do this fastest. Long recordings last longer, and they still have landmarks. The same thing happens with lo-fi playlists: once you recognise the repeat, the sound is no longer background.
If you use recordings
- Choose long ones. An hour is better than ten minutes.
- Avoid thunder, birds and passing cars. Landmarks are what you end up recognising.
- Plain, even rain lasts longest.
Rain that is made, not recorded
The other way is to generate the sound live, so there is no stretch of audio to come round again. Noise is the raw material. Shaped one way it is hiss. Shaped another way it is rain on a roof. Because it is made fresh every moment, there is no seam.
To be straight about my own project: Ambient Sound Online has no rain. It works on the same principle with different material. Shapes drift and make a sound when they meet, nothing is recorded, and nothing repeats. The free world, Ocean, is underwater: slow tides, sonar pings and distant whale calls.
Sources
- Buxton and colleagues, 2021, PNAS: a synthesis of health benefits of natural sounds
Try it: if what you like about rain is that it never repeats, Ocean works the same way. It is free and starts in one click, with no account.
Open Ocean, free