Bushmeister made an interesting speaker using the volt dome
http://https://www.diyaudio.com/forums/multi-way/307837-balls-prestige.html
http://https://www.diyaudio.com/forums/multi-way/307837-balls-prestige.html
camplo you asked about some papers on the audibility of reflections, I came across these from Soren Bech which sound very much like the project I mentioned.
https://backend.orbit.dtu.dk/ws/portalfiles/portal/4415806/Bech.pdf
https://backend.orbit.dtu.dk/ws/portalfiles/portal/5317430/Bech.pdf
https://backend.orbit.dtu.dk/ws/portalfiles/portal/4425895/Bech.pdf
https://backend.orbit.dtu.dk/ws/portalfiles/portal/4415806/Bech.pdf
https://backend.orbit.dtu.dk/ws/portalfiles/portal/5317430/Bech.pdf
https://backend.orbit.dtu.dk/ws/portalfiles/portal/4425895/Bech.pdf