I can relate to those descriptions of arm tube as well as mounting bases, although there are often other factors at work as well. In my case, the Siggwan has a solid cocobolo arm tube, yet I like the sound on the brass pod more than on the aluminum armboard. I can't really draw firm conclusions based on just the material because one is a detached pod and the other is rigidly attached to the table. This is the first time I have tried a standalone pod so I can't say how much of what I am hearing is due to that aspect and how much is due to the material.