Shoot, all he has to do is switch to electric motors. We have been filling speakers with acoustic cotton or poly for almost a century. Thoughts? The best enclosure is no enclosure ( except for subwoofers)
Thoughts for Future Speaker Designers
I put together a video of some design thoughts to consider.....
https://www.youtube.com/watch?v=--c0tiIZG6o
https://www.youtube.com/watch?v=--c0tiIZG6o