Reply to S2 Heaphones Output volume issue

Hello,

Bought the S2, but noticed when playing on a gig that my max volume for the headphones wasn't loud enough.

What this could be??

• Headphones quality bad?
• Headphones not being able to insonorize the exterior sound?
• The s2 louder volume is not enough, when playing on a loud gig?

I am using some Aerial 7 Tank Mondrian headphones http://www.aerial7.com/product/street/tank/mondrian/

Thanks!!