My front left and right speakers are inside my wooden TV cabinet. It has two enclosed spaces for the speakers with speaker grill on the front, particle board with holes drilled for ventilation in the back, and solid wood on the four sides. There seems to be some unwanted reverberation inside the cabinet. I’m considering putting some acoustic foam insulation inside the cabinet to reduce the reverberations. My speakers are rear-ported bookshelves. What would be the best way to reduce the reverberation?