What could cause a violin to sound hollow on G string while having a overwhelmingly powerful E string?

I've tested a lot of violins and I noticed some violins have the tendency to sound "hollow" (to the ear) on the G string while some others have a warmer and deeper tone. What causes this? Is it the age of the wood, bass bar, thickness of the plate, a too thick bridge...?

Also what cause an E string to sound more powerful than other strings? (Same string set). Is it sound post placement? Bridge adjustment? My violin has that particular issue if I may call it so.

I'd be glad to hear your thoughts, share of experience and all :)