Drilled out
OK - I have a fair bit of experience on this.
On the LO setting you get nothing, and on the HI setting not much more inside the case.
My first step was to complain to the GoPro manufacturers who were very helpful. They first told me to try with the seal off which I did. This worked reasonably well on HI (still not much on LO) but gave a lot of wind noise and the volume was still quite low.
I posted my videos on YouTube and got the manufacturers to watch. The next thing they told me was that, as long as I'm not ever wanting to submerge, I could drill out the case with a small drill. But they told me specifically where to do this. It is in the back, top left where there is a circle moulded into the plastic case. This position is they say the best due to the location of the mic and the integrity of the case.
This worked much better, on HI (still no good on LO) but the recording sounded like the end of a tunnel. Next step I enlarged the hole to about an eighth of an inch. This was the best result yet. However, when the camera is turned so that the hole is not shielded from the wind, you get bad wind noise that overloads the camera electronics and sounds like really loud static. Next I tried some foam inside by the hole. Not much better but a slight improvement with the static. I reckon this is the best I'm going to get.
The next logical step is to make the hole bigger - say a quarter inch, and use the LO setting, but I haven't done that yet. (You can always tape up the hole if the sound gets too loud I figure, but these steps are not reversible
)
Whatever you do, DON'T try to drill out a hole above the mic. As this is on the top, I guarantee you will get horrendous wind noise (if you ride fast) which will overload the electronics causing very bad static noise.
No doubt about it, audio is the Achilles heel of this camera.
