The wooden bell sounds fatter and fuller to me, but it's a very different shape, so unless two bells of exactly the same internal geometry were compared it proves nothing about the alleged effects of wood v metal.
It's interesting to see the shape of the wooden Backun bell resembles some of the things you see on old basset horns, so the popularity of these wooden bells with classical players may be a reaction against the ongoing trend for instruments to be louder and brighter than they used to be. There was someone on Radio 3 a while ago talking about playing Elgar on vintage instruments who mentioned that full fortissimo these days is louder than it was in the 1930's and the timbre was more muted in those days...
There seems to have been a lot of debate on other woodwind forums about these wooden bass clarinet bells, so you can do a bit of googling if you want to.
As players we perceive things that no one else will notice eg differences in reeds etc and a microphone does not detect sound the same way we do, it turns a 3 dimensional sound pressure wave into a two dimensional voltage and can only tell you what was happening on the surface of a small diaphragm, so recordings are a poor substitute for the real thing and as such it's difficult to form an opinion without having direct experience.
If anyone ever gets to play one of these wooden bells, do let us know
I wonder what happened to these wooden saxophones -
Nova Wooden Saxophones