Do any of you use re-entrant tuning, or know of anyone that does? Nashville excluded. That is a tuning where the lowest string, eg 6th string is tuned higher than one of the other five strings? - Like a 5-string banjo or soprano uke. I've done it a few times, but it doesn't seem very common, except for Nashville tuning.
I think it's probably not so common because on a guitar it really doesn't have any major advantages. The Nashville tuning is only used to mimic a 12 string and so it makes sense. And if it was practical, 12 string guitars would have octave strings on the first two as well, but that's another story.

I use this one reentrant variation of th3 C6 tuning (CEGACE) on lap steel guitar. I have an 8 string so I have an extra high G and the low C is tuned up to a C# to make an A7 on the low strings, which is common for C6.

So my 8th string is a B that is pitched between the A and the C to create a maj7 chord. Now, why is it on the bottom instead of the middle? Because otherwise I couldn't strum that lovely C6 chord if it was in the middle. I also would be unable to strum the half diminished chord on the bottom (bC#EG) because the A would be in the way.

The E9 chromatic neck on the pedal steel also uses a few reentrant tuning, with the first four strings being EG#D#F#. This was added after the fact, since the tuning had originally been BDF#G#BE. Then the high G# and middle E were added. Herb Remington originally added the high D# and F# to the bottom rather than the top, but they were moved to create the modern BDEF#G#BEG#D#F# tuning. This is useful because, similarly to my C6 tuning, it puts the less-used D# and F# out of the way.

With the banjo, the 5th string is used to allow the thumb to hit the high and low notes. A lot of rolls won't work if you try and do them without the high G since you would either need to cross pick or use another finger.

Although banjo playing has evolved around the 5th string, and so most styles of 5 string banjo playing would not work the same, as well, or even at all without it. But when the instrument was created... well, a new instrument is a blank canvas and playing styles evolved around them and they evolve to better accommodate playing styles. Such is the case of the banjo. The instrument originally had four strings, gGBD. Although back then it was tuned lower to dDF#A. Joel Sweeney added the low G in 1841 to give the instrument more options for chording and melody. Then shortly after he decided to raise it all up a fourth. At some point somebody decided that the high G got in the way when flat picking and so started taking it off.

The thing with guitar is that reentrent tunings, just aren't necessary. Since string instruments have traditionally been strung with the majority of strings strung low-to-high (and even in the case of banjo, ukulele, and steel guitar, only one or two strings are "out of order"), it's a bit counterintuitive to change that without having a good reason.

And there really isn't a practical advantage to reentrant tunings on guitar the way there are on other instruments.
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^^^^ Good discussion. I'm strictly a fingerpicker, and I've tried using it in the same ways as the banjo fifth string, (as dGDgbd) for slide but it really has only ended up sounded like a novelty rather than as a useful melodic tool. A couple of the songs in my sig link, "John Hardy"and "Worried Man" are done like that, but I'm not particularly happy with them. I was hoping someone could offer something inspiring.

I've got an 8-string lap steel, and I can't find an open tuning for it with which I'm comfortable. I've also tried a re-entrant tuning on it, I might give a 6th/m7 tuning another go. It is about finding a tune I would like to play, and those country type arrangements really aren't my thing for the most part.
For 8 string I recommend either a 6/13 tuning or a 9.

A6 - F#AC#EF#AC#E - the old Herb Remington western swing tuning
C6 - ACEGACEG (same intervals but a flat third higher)
C6/A7 - XC#EGACEG - The X can be A, Bb, C, high b, etc... lots of options
E13 - BDEG#BC#EG# - Don Helms had a low A but almost never used the A or D string
E9 - BDEF#G#BEG - basically the E9 pedal steel minus the chromatic strings
E9 - EG#BDF#G#B - an older E9 variant without the middle E or high G#

I have only ever used C6/A7 on lap steel but obviously I use E9 and C6 on pedal steel.

Also 8 string resonator players often use G6 (EGBDEGBD), which is the same intervals as the basic A6 and C6 tunings, but with the Dobro Open G notes all present.
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Last edited by theogonia777 at Jul 12, 2015,
Thanks. That C6/A7 looks interesting, probably using a low A to get A7, Am and C. I could work that into my interest in blues.

I have used a basic 7th chord on the 8-string, putting the 7th note on the 2nd string and the rest an open major chord. It isn't bad for blues/jazzy sounds, but the 6/7 could well be better.
If you want to go with an E7, most people tend to put the D on the lower end, so maybe EG#BDEG#BE or EBDEG#BEG# for an 8 string. Though you are of course better off putting a 9 or 13 in there somewhere, at the cost of one of the lower strings usually. It also depends on what sound you want. I play mostly country and so I'm mostly playing high stuff, so I don't need the low end of an E7 tuning.

Keep in mind with lap steel you will always have to sacrifice something. More different notes means more possible chords but it also means less of the same notes and so a loss of inversions. Also putting notes like 9, 11, or 13 in the middle means tighter intervals, which means less range. Like I said, the low strings usually go. A lot of blues, rock, and bluegrass players tend to like those low notes.
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Yeah, open tunings really work best for what I play - folk and blues - so D, E, G or A, with wide intervals on the low notes to help deal with implied minors, but it would be good to add a bit of interest with 7th and minor intervals. It going to mean retraining my picking hand though. Still, what's the fun if there is no challenge?