Thanks Geoff. I must admit, I've seen (heard?) many more under damped cabinets than over damped! Most problems seem to revolve around inadequate front baffle mass/stiffness. You need both high mass and stiffness to lower resonant panel frequency AND to limit panel excursion to minimise distortion. It always puzzles me to hear comments about over damping the inside, when it does require at least 70mm depth acoustic foam and wool all the way round, with twice that behind the driver!