- what you describe as a louvers is a diffuser. It reflect more than 80% of sound, but diffused.
- the design has nothing to do about being ornate or not. It is optimized for efficiency. The wings diffusion pattern is superior to a classic quadratic diffuser.
- Goodwins room doesn't have any diffusion. Zero. It avoids parallel walls, that's it. It doesn't mean it cannot be a great sounding room. Unfortunately with room design, part is science, part is luck.
- I don't want to derail this thread.... but the the whole topic of Golden ratio for rooms dimension would justify a long explanation on why it is of little help on room design... as a start, the Golden ratios are calculated for a sound source positioned in a CORNER of a room. Do you put your speakers in the corner?
-Helmholtz resonators address room resonance on a narrow frequency band: see it like an absorber, which a narrow frequency response that you can tune. That means if you tune them on room nodes, you can selectively flatten the frequency response of the room. Only problem is you need quite a lot of them to work well. But they have the advantage to go much lower in frequency than soft absorbers like fiberglass.
You should read the book from Toole, and everything will be clearer to you. I did read a lot of books on acoustics, this is the best by far.
