Scientific study exploring the benefits of natural sounds. It demonstrates an overall positive result for most people, both when hearing the sounds inside or outside. Some sounds worked better for soothing nerves, such as water.
The overall mean effect size for health and positive affect outcomes was 1.63 (95% CI = 0.09, 3.16), corresponding to a 184% overall improvement in groups exposed to natural sounds relative to comparison groups (Fig. 1). The large variance in effect sizes was due to one study with particularly large effect sizes (28). The overall mean effect size for stress and annoyance outcomes was −0.60 (95% CI = −0.97, −0.23), corresponding to a 28% overall decrease in groups exposed to natural sounds relative to comparisons (Fig. 1).
https://www.pnas.org/content/118/14/e2013097118/tab-article-info