The BDI Valera 9724 is heavy, weighing a hernia-tastic 61kg, and comes with quite a few small parts. It took two of us about 45 minutes of heaving and swearing to assemble.
Once put together, though, this is a very stylish solid wood frame holding slabs of glass. It all attaches to a swivelling platform, which you can restrict. It doesn't lock completely though, so at the very least it will swivel by about an inch.
When put on the glass-only middle shelf, our system sounded harder and brighter. And to round off the test, using only the bottom level of wood and glass the sound conveyed was somewhere in between.