I have a 12 x 16 room with 7 1/2 foot ceilings. Yeah I know the cylinder you speak about, but I was looking for a diffuser cylinder all the way around.
Diffuser are a pain in the ass to buy with all the various designs and not seeing the one I really want unless I have to spend two to $3000. Let's face it lots of them look pretty crappy.
Frankly I’m concerned if I put diffusers in my room it may enhance the clarity of the music moreso. So I’m not sure if diffusers would be a good thing. Although it would be nice to dull the higher end frequencies at times which can be harsh depending upon the recording.