You just put 100W of equipment into a completely enclosed box with no airflow. Aren't you worried about heat?
yeah, first thing I thought of too. Maybe he is trying to "Kiln-dry" his lumber?
EDIT: @DennisD7 -That sound absorption material, is it fire resistant? If there are ANY sparks in your rig, it makes for nice kindling.... http://youtu.be/D4xaWMKBlw4