It's not that these alignments are underdamped, it's just that they result in high-efficiency midbass with no deep bass. To me, a high-efficiency speaker with a lot of midbass can sound sort of thick. I hear this in mini-monitors when turned up loud too. They're making plenty of low midrange and some upper bass, but no deep bass foundation. It just sounds weird to me.

Maybe try this new speaker of yours with a sub? How does that sound?