Rain is like a waterfall....The atmosphere become ionized...
Ionization act on the body of the listener and in the room physical atmosphere making sound waves traveling and interacting more " easily" in the room ...
«Raining also causes an increase of negative ions in the air; negatively charged particles that come about because of lightning and the friction between the rain and the air. These ions can significantly improve the nervous, cardiovascular, and respiratory systems, helping people feel more comfortable and relaxed.»
I own a grid of ionizers, three different complementary types in my room....With the low cost Schuman generators grid they are my main non-Helmotlzian devices for my room acoustic control... 😁😊 All that at very low cost and with a big impact...
Ionization help a lot to create an intimate sound effect like listening to an headphone but the sound is outside the head 😊 but ionization alone will not be enough, i used a foldable wood screen as a psycho-acoustic devices to work with speakers A and B for ear A and B loke a lense balancing direct waves and reflkected waves.... But it is another matter not related to the OP question...
If you think i am "nut" read this review about Mr. Ishiguro costly acoustic panel using tourmaline as ionization device...And Mr. Ishiguro is anything but nut in Japan audio circles...
https://positive-feedback.com/reviews/hardware-reviews/acoustic-revive-rwl-iii-absolute-acoustic-panel/
What are the audible effect of ionizing the room?
I will borrow the words of the reviewer, they describe better than i would have, the effect of ionization, even if here he spoke also about acoutic panels where the ionizing tourmaline is indeed integrated...
«The panels do not modify the colors, but they bring them out, they do not add top or bottom, but better focus the edges of the sound spectrum. The sound is much more engaging with them and also more relaxing. Virtually everything is improved—from space, through color, to dynamics.»
This describe well the effect i feel with my ionization devices, i dont claim that my cheap devices can replace three panels costing near 8 ,000 bucks for the three but my ratio S.Q. /price ( under 200 bucks) is over the roof...
I wrote this to motivate people to create their own devices and experiments....