has anyone tried to laquer the inside of the box? I did this to a earlier build and it sounded a lot like a banjo. I would think that the wood absortion inside the box would make a difference in volume and tone.
It sure has to have some effect... I've always found it odd that virtually all wooden instruments are kept unfinished on the inside. I would guess that the "fuzz" on raw or just sanded wood, could absorb some high frequency sound energy.