Hello Sten, the prototype was born to my curiosity about non-conventional tools, I'm not a good musician, maybe that's why I dedicate myself to the violin, but I like trying new sounds and possibilities of the acoustic altoguitars me back .... the lute, the idea of having greater harmony and a sound and durability with a parallel resonant chords of sympathy, but if the guitar is well tuned at the level of speaker!
The pine inclined to increase the capacity of preparation of the instrument, ie the attack and brilliance (it has a heavy load at the expense, and this is a problem to occur), but still take me with pliers is still a prototype, As I said earlier, unfortunately I made a mistake in the intonation of the soundboard!.
The holes behind, give greater extension of the shaking table make the most of its internal frequencies, increase the bass a little perhaps at the expense of acute, but the frequency of the instrument and its range should resolve this ..... in my case the case is still too small to generate 80 Hz or less bass in the first harmonic!
hoping to see complete tool does not explode!
Greetings Walter