Recording the sound of the rain is tricky, and as usual, there are many possible approaches. Here's a method I tried.

Goals

My idea for recording the rain is to try to combine a number of goals:

Construction


The mic setup, under the foam rain shield.

My solution was to use reticulated foam glued to a waterproof board over the mics. Reticulated foam is a very "open" foam — it's kind of like regular foam with all the bubbles popped — and the idea is that it would slow down and stop the raindrops gradually, without splatting. It will also drain. Regular foam would get waterlogged quickly, and make splats. I used three layers of foam, with gaps between, to try to isolate raindrop sounds more; this sort of worked.

The board underneath was just foam core; since this is paper-covered, I sprayed it with laquer to waterproof it. A strip of wood was glued under this, with a threaded insert glued into it to attach the tripod plate. The rain shield is placed on one tripod, and then the mics on a separate tripod underneath it, for the best sound isolation.

This worked pretty well. Large drops still made an audible thump; the best solution to this was to avoid being under a tree, as trees collect the water into big dollops.

Testing


The rain recording rig in use. The towel is to stop drops hitting the tripod. The recorder was 60 metres away, on the end of a long cable, in the car.

Here's a sample recording made with this setup. The mics were 2 MKH 8040s, in an ORTF blimp, under the rain shield.

More Pictures


The rain shield and blimp, from the front. You can just see the two separate tripods.

Side view of the rig in use.