Hey Shredded, when I started out I was recording my audio separately via my phone.
I have a Samsung Galaxy S8+, I used the AKG headphoens that came with the phone, though I wanted it to be my dedicated mic so clipped off the earbuds so that it was a single wire running to my helmet.
Now whenever I record external audio I still use that same headphone mic but I record into an old iPod touch, there's a recording app that I found that allows you to adjust the gain and pitch so things like wind don't overload the audio file.
One thing I can tell you is make sure that you do a proper wrap on that external mic, use mic foam, then deadcat, and if you're like me add an extra layer to clean it all up, I used a bandana or microfiber cloth on mine.
I prefer to record with a secondary device and sync audio as its not a big deal if you just clap at the beginning, thats the whole idea behind a clap board. Many editing programs can sync for you such as in Adobe Premiere. So I use an app called Voice Record and the Audio-Technica ATR-3350IS Omnidirectional Condenser Lavalier Mic with Smartphone Adapter to record audio. I don't have a deadcat on mine, I use two foam covers over each other. I then attached the mic portion ot he cheekpad in my helmet right next to my mouth with velco.
I think I get pretty good, clear audio for my vlogs with this setup and the powered mic is a bit more upkeep, but worth it in my mind. And the Voice Record app allows for control of the gain, as well as other level, to get the best audio you can with your helmet and bike noise.
On my channle I have a video called My Vlogging Rig that shows my setup if you want to take a look. I also explain the iPhone handsfree headphone/mic setup if you have a pair that you don't mind removing the headphones from to record audio.
We have a few hidden forums and features that you can't see until you login or sign up. We only send about 4 emails a year and never sell anything. We're a global community for bikers who like to record videos. We run this site for fun