Yamaha G-255S and Tornavoz experiment

This is an experiment about adding a tornavoz (a cylindrical piece inside the soundhole), and the effect it has on the sound.
Basically, this confirms that the tornavoz affects the basses, making them sound deeper, like if you applied an equalisation to it, but it is natural.
Also, I took advantage of the 3D printing and added a fretboard extension, where I was able to add a fret.
This guitar (1979 Yamaha G-255S) is now for sale, if you are interested.