The Mannheim Steamroller Christmas concert December 15 at the Fox Performing Arts Center in Riverside California was a complete disaster! We were greeted with a audio explosion before the concert started. They had technical difficulties with their audio and computer systems which was actually causing extremely large booms like Sonic Booms that were death-defying and actually nerve rattling. They could not rectify the problem throughout the first half of the concert with attempts to stop and fix it. People were leaving in the first half of the concert due to that problem because it was just too scary and loud and disturbing. When they proceeded to start up again after 20+ minute delay, the musicians were greeted, as the guests, with a sonic boom that completely ear shattered everybody. We left when the second half started and the first erupted sound hit all of us again. Also, as we watch the musicians perform, it was completely apparent that the concert was 'prerecorded' with minor instrumental effort. Heavy drum and bass overlays masked with the videos, really - dated and aged. And we have heard nothing for the Riverside Fox Performing Arts Center for this sub par performance as we left or since. I had planned months and months to surprise my wife for Christmas this evening. It just didn't turn out the way I wanted it. A very disappointing evening for one to remember.