Guitar-maker Fender says the sound can be traced back to the early days of the doom metal group Pentagram. As far back as the 1970s, guitarist Victor Griffin leaned heavily into drop B tuning.

Included so far are Double drop D, Open D, Open G, DADGAD, Bass guitar, Bass/standard split (bottom two strings shifted an octave down), Standard tuning doubled an octave down, Twelve string and ...