Hey guys, I've got a question. Last Saturday I had a gig with a big band using my DB and my Eden 2x8 combo. We were on a portable stage. I had my amp set ontop of the dummers low tom case positioned behind me to the right. I was able to get good volume without feedback. Well, Tuesday I had another gig with the same band and same equiptment. Due do space restraints, I had the amp on a chair about 2 feet immediately to the right of me. I couldnt get the volume I wanted without feedback. Plus, I couldnt arco at all without MAJOR feed back. This was on a concrete floor.. The results are exact opposite of what I wouldve thought. I thought the stage would be more resonate and the amp behind me promote more feed back. But, I got feedback on a concrete floor and the sound from the amp going straight out instead towards me.. Any help or suggestions??