The Zoom H1n has three settings that can affect recorded volume.
Auto Level, Page 19 of the manual.
Noise, Page 21 of the manual.
Limiter, Page 22 of the manual.
Of the three, Auto Level can cause the problems you have.
However, setting the H1n to record thunder and rain will be a challenge. Rain sound (really rain hitting something) is nice quiet, even “pink noise” sound. Thunder is loud enough to move your shirt and it’s very low pitch so you can’t even hear about a third of it. My guess is you’re going to get good recordings of one or the other. Get some good rain sounds and let the thunder overload. Then go back and set levels for the thunder.
Page 18 of the manual.
…and mix them later in Audacity post production.
This isn’t an easy recording job.
If I had to do this in one pass, I would probably set one of the Low Cut Filters (80Hz) and then turn the limiter on, but not the auto level. That and record rain hitting leaves on trees, not your roof or the street. That gives a much more satisfying shshshshsh sound.
Fair warning, you’re going to get a “Hollywood” thunder shower. It’s not going to sound like it did when you were there.
It depends on your show. How are you listening? I have a killer sound system and powerful sub-woofer that can shake the wine glass. That’s perfect for this job.
It’s two different tone groups. One group is the actual theme that sounds like an electronic tone generator or keyboard with fake flutes. But there is a second group that sounds like thunder. I did the tonal analysis. It’s the same tone as the 16 foot pipes of a theater or church organ.
Can you hear the low pitch group? Does it scare the cat?
Did you ask how he had it set? As I posted, you have the symptoms of Auto Level. Something very loud comes by and it takes the system a couple of seconds to recover.
I’m perfectly delighted with my H1n although it did take a while to get used to how the buttons worked.
In April I took it to a windy beach with the goal of making an acceptable voice recording no matter what. I kept making changes and slating everything (this is with the foam blast filter and the 120Hz low cut…) Eventually, I got a recording where the recording meter didn’t go nuts and I didn’t sound like an artillery barrage. I can’t wait to do the sound analysis.
If I had to do this in one pass, I would probably set one of the Low Cut Filters (80Hz) and then turn the limiter on, but not the auto level. That and record rain hitting leaves on trees, not your roof or the street. That gives a much more satisfying shshshshsh sound.
You don’t have to worry about maintaining perfect recording volume for the rain because rain sound and microphone recording error noise are close cousins. Keep it low so the Limiter doesn’t have a lot of work to do when the thunder comes.
How are you keeping the H1n from getting wet? Microphones don’t much like water, and it’s not just a water problem. There was a poster who wanted to do what you’re doing and his complaint was the recording sounded like rain hitting his umbrella. That’s correct. It can also sound like a wooden back porch or any other rain shield.
In literature, there’s no shortage of passages like “he considered his options with the rain drumming on the roof.” That’s roof noise, not just rain.