Mic Recording Level.
I mostly only use this camera only for concerts (loud rock concerts) so this is what I would suggest...
Unfortunately there is no way to adjust the recording level.
Someone in this thread mentioned to place the Wind Noise Canceller to High. I have not tried that yet (I have mine set to Medium).
I have learned and experienced that "Zoom Mic" set to ON is not a good thing. This amplifies the sound the more you zoom in. It's already loud at the concerts I go to so no need to amplify audio. Turning it off, it sounds much cleaner.
The audio recording on this camera is atrocious. Even my older and much cheaper pocket Panny cameras sound better. If I recall correctly, the M4/3 and larger sensor Panasonic cameras are pretty good with their mics and have much cleaner preamps. Of course, still nothing like external mics/preamps/recorder.
Anyone do an audio comparison with this camera and the 1" sensor pocket Sony RX100VII? I have interchangeable lens cameras by Sony and it sounds so much better, but not sure how the compact Sony's are. RX100VII doesn't have the same zoom range, but the lens is sharper so you can crop in even more than the equivalent to the ZS100 and it will be sharper. Works a little better in low light too. Plus has a mic input. Has so much more that is better about it for me (and a lot of other things that are better, but they don't all matter much because I only use it for 1 purpose), but it cost about 3X as much as I got the ZS100 new.