Why Jason uses One-Bass Drum on the concerts??

It most certainly takes up less space on the stage and in a van. If you can use the double pedal and are happy with the response from a single bass set up, why change?

Glenn
 
also you have to take notice of jason's height. He is small, and therefore has short legs, and a double bass drum set is uncomfortable when you have short legs, because the drums make the two pedals be separated.