Nashville tuning is actually a guitar tuning used by many studio musicians in Nashville. To get an acoustic six-string to really ring through in a dense mix, the studio guitarists often string one up with the octave strings from a twelve-string set. The result is a tuning that has a narrow bandwidth that really cuts through without hogging up the midrange frequencies. The tuning works great on six-string banjo. On my banjitars, the scale length is 26.5 inches, which is kind of long for stringing up that octave G on the third string. I tune mine down one whole step and it works great. I don't break strings and to play with other instruments, I just capo up two frets. This video shows you the details of the tuning.