In fact, these glass-enclosed speakers work amazingly well. The advantages of glass are high density, rigidity, and (with the aid of a damping chamber behind the drivers) "no vibrations," presumably meaning none of the bad kind. Warmth, depth, and solid controlled bass were what I heard and quite liked. Waterfall will also offer on-walls when the French manufacturer gets its U.S. distribution nailed down, which should happen any minute now.