MartinLogan Dynamo 800X powered subwoofer

In the late 1980s, when I began reviewing high-end subwoofers, they were big and heavy, difficult to move or find space for in a room. Their controls were always on an inconveniently positioned rear panel, and there were no built-in automatic room-optimization options or parametric equalizers. Velodyne's 105-lb, downfiring ULD-18 ($2570), ca 1989, was typical: Two people were needed to unpack and move it; it was powered by an outboard 400W amplifier, connected inconveniently with a speaker cable and an RCA-terminated interconnect for its servo control; and its controls were on the bottom of the cabinet. Changing its crossover frequency involved soldering new resistors onto a printed circuit board inside the amp.