Originally Posted by keep it simple
Of course, like everything, it's a combination of factors, but in the case of the Zelcova, rigidity plays a big part. Although the shell is quite thick, it's not that rigid compared to a ply shell of similar thickness), & that lack of rigidity suppresses high tone generation + shortens the fundamental.
My thought was that this drum has absolutely no glue anywhere, unlike ply drums, stave drums or segmented drums. No knowing the age of the wood it could still have a relatively "wet" soft property to it. This would make it a bit softer and deaden some high tones. Just a thought.