Just ran across this company Acoustic Fields out of Arizona.
They have some nice products and some are quite pricey.
I believe what they use is some type of carbon in the interior and they weigh in around 225 lbs.
Their diffusors look real nice,also they have that carbon base in some of the them also.
Looking at 3000+for a diffusor
,but all in real wood ect.
Here's what I was looking at,
