I'm happy to report that the audio test was mostly a success.
@zonkiel I believe it would do what you are looking for with some testing. My bike test was with the mic clipped behind the wind screen of my GSXR to help cut out wind noise, and was able to capture some pretty solid bike sounds. I did not test the mic toward the rear of the bike, in hindsight this would have been a better test for your purpose, but I believe with some testing it would do quite well.
The audio is naturally synced with the video through the Gopro, but allows cleaner and more adjustable audio than the Gopro itself.
TLDR; It worked, and the Tascam DR10L was filtering out lows and highs just as it normally would while recording. That meant no wind noise or high peaks during my recordings. More info below for those interested in specifics.
My test setup as follows: Purple Panda Lav mic > TRRS to TRS adaptor > Tascam DR-10L > TRS Male to Male cable in the DR-10L monitor output > GoPro external mic adaptor > GoPro Hero 10
DR-10L settings as follows:
Mic Gain - Low
Low Cut - On
Limiter - On
Auto Level - Off
Sample rate - 48kHz
Bit length - 24bit
WAV format
Test videos included a hiking trail, working in my garage with hammers, air tools, and the like, and a motorcycle ride.
Each test scenario was recorded at 4 output levels from the DR-10L, 25%/50%/75%/100%
All tests had pretty horrible audio at 100% output as expected.
- (Peaks, crackles, and quiet sounds over amplified.)
Air tools and banging hammers peaked and crackled at 75% output.
- (More sublte noises like crunching leaves and motorcycle sounds were more inline with their natural ranges.)
Very smooth and filtered audio at 50%.
- (All sounds fell into their normal volume ranges and gave a natural sound)
Quiet but smooth audio at 25%
- (Would likely require amplifying audio in post processing)
Using the external mics of the Hero 10 as a baseline for decibel output the recorded audio came in roughly -4dB at 50% volume and roughly -12dB at 25% volume.
The PPanda mic has been pretty sensitive in all of my other tests, so a less sensitive mic would likely yield better results on top of the adjustability of using the external recorder as a filter of sorts. Your mileage may vary as always, but I believe it's a successful test.