I do believe that you've read that about electric guitars, but I'm sorry, I don't believe for one minute that different body materials will make a difference in the tone of a
SOLIDBODY electric guitar. It's the different types of pickups, different gauge strings, electronics, etc.
It sounds like a bunch of poppycock to me.
Yes wood absorbs, or vibrates sound differently than plastic or metal, etc, but how can that affect the sound in an electric piano (that doesn't have an amp and speakers built in) or a solid body guitar?? It makes no sense to me whatsoever. You aren't amplifying the case/ body in any way. You are amplifying the tines, reeds, strings, not the case.
I'm not trying to argue with anyone, I just don't see how these changes would alter the sound.
