Of all the electronic items made over the years, the one that appears to have changed the least is the speaker. They have always been pretty much the same. Originally they used electro magnets, then changed to fixed magnets. The cones have used different materials, but mostly paper and plastics, some with a foam at the edges. There was a time when a small cone was added to the middle of a large speaker to act as a tweeter, although they were not very effective and is no longer in use. The coils have always been pretty much the same. I see little change in speakers in the future, other than the trend seems to be smaller speakers which can still deliver high power. However there seems to be limitations on sound quality with smaller speakers. Also, plastic cabinets will never replace real wood, and never sound (or look) as good as wood.
The one thing that I have noticed are the Bose speakers. From what I read, they use an enclosure which directs the sound in a way that causes air pressure to move inside a room, and thus makes more powerful bass from their sub-woofers. From what I understand, the speaker itself is the same, but the cabinet is different. It's capable of delivering more bass from less speaker size.
It appears that Bose is very closed mouthed about how they achieve this. Their speakers are probably the most expensive available, so it makes sense that they keep secret how they design these cabinets. My reason in posting this is because someone must know how they do it. But I have not been able to find anything on the web.
Does anyone know of any websites that explain in detail how they design their enclosures (cabinets), and what is used? I have always built my own speaker cabinets, and would like to try a similar design.