There are no tonal differences between a 3-piece body and a 1-piece body, as the glue used is stronger than the wood itself, and the amount of glue used is about as thick as a sheet of paper. Saying otherwise makes no sense, as sound waves are much like electricity; (think of the sine waves you'd see on an oscilliscope for both sound waves and electricity) imagine two thick rods of copper wire. Using a multimeter (or fluke) test the resistance from one end of the copper rod to the other...you get 0k ohms. Test the other rod...same results. Now, take a sheet of steel plate, the thickness of a piece of paper and sandwich it between the two rods and measure the Ohms between one end of the copper rod and the end of the 2nd copper rod...same results. 0k ohms. (Just in case you didn't get what I was talking about, the copper rods represent the body wood and the steel plate, the glue) On top of all that, it doesn't even matter, as sound is much like water and electricity... it follows the path of least resistance, which means sound travels with the grain, not against it, and so the sound that's flowing through the body runs from the bridge to the neck and moves its way to the nut, all the while the strings are sending vibrations (sounds) to both the neck and body from every single area, from the nut to the bridge. Sort of like an accidental symphony. Besides, we're talking about electric guitars here, not Stradivarius violins. For someone to say that they can definitely hear the difference in sound between an electric guitar with a 3-piece body and a solid body, I'd have to say that they have a gift that Mozart himself didn't possess.
Class dismissed. 😆