I am curious as to why GoPro so good give 2 cases (waterproof & non-water proof ? If they already give the waterproof one, why is there a need to give another non waterproof one ?).
The sound is very muffled and pretty much unusable when recorded using the waterproof case. So if you need to record the sound, you should use the non-waterproof case. Even then, it's only mono recording.