I’m curious about this statement. I have two harps made of walnut and neither one of them sounds “muddy” to my ears. Very rich in the bass, lots of sustain, and bright with a fair amount of attack in the upper octaves. Maybe this statement is in reference to the sustain?
And yes, if it is only finished in walnut, I can’t see where that would effect the sound. Maybe there is another factor in play here besides the wood.
Karen