DEEP GUITARS
In experimenting with pickup designs for string instruments, I have stumbled upon two designs, very different both from one another and from more common pickup configurations, which have in common that they give rise to a tone that is unusually full in the bass. To bring that out, the two guitars seen on this page are tuned a fourth or fifth below normal guitar tuning.
In the video linked below, Deep Guitar is one of several guitar-like instruments discussed.