The volume up button is prominent, but never on being in the right place. I removed the helmet three times to check.
max max, sound is comfortable, but could be even stronger. Maybe it was the sound of my film that was too weak? there is always a way to boost anyway, at least in VLC.
I did, in the end, only one small regret: the headset is a bit rigid on my big head. The headphones can be adjusted (both sides), but the helmet pressure sensitive. At least it does not fall!