Thanks for all the interest and replies, there are a few interesting things to check out. Been away to the GFs and the internet ISP will be running too slow to look things up till tomorrow through over use...so will look at those things more.
Most will recall I built this guitar to explore these kinds of ideas...
guitarnuts2.proboards.com/index.cgi?board=wiring&action=display&thread=5970The guitar is fender scale so a little longer than my acoustic and strung 10-56 so heavy in the bottom.
The trilogy will tune each string to 3 stops. The highest is standard, I've set it up to detune each string a semi tone, so max of a step...however I recently allowed the low E string to drop in full steps...so E-D-C
This gives easy access to open G, open D, DADGAD and even some odd things like the C-G-D-G-B-E variations like I've come up with the other day. Obviously it is very easy to just 'drop' D or similar and there is always the tuners as well.
I've played around with a few things, but it is tricky once you have the standard tuning so ingrained and mapped in the mind to change...absolutely!
There are a lot of great players out there though exploring altered tunings with great results. One thing is that it does give access to a wider range and interesting sounds.
With the solo guitar things I am exploring, the standard guitar 'shapes' are avoided largely anyway though I wouldn't want to lose what the standard tuning offers. For most things and for overall playing, being able to grab a whole chord or get around with a finger per fret kind of scale thing it is king.
Stanley Jordan tunes all in forth so things are symmetrical (avoiding that b string maj3 shift in standard tuning) but is not really suitable for conventional guitar playing.
sumgai, decades back I too tried the tune in 5th thing too possibly influenced by the above and fripps 'new standard tuning' kind of thing, though I didn't know what it was at the time and he was not publicly saying then.
I came across a transcription of a nice arrangement of stings 'moon over burbon street' by soYmartino that uses dropped B...so tuning the E all the way down to B only. It is kind of cool, the low E is now on the fifth fret, the open A and the low B giving you your I-IV-V bass notes and a lovely 'string bass' kind of depth to that open string...and there is a bit in that without changing all the strings, just the one.
I was trying to make an arrangement of 'time after time' again, there are a heap around, but thought I'd drop the low strings down to C and G to get that nice low C tonic and to be able to reach notes on the high string on the 8th fret with the F bass, now on the fifth fret. The open G string is good for the V chord of course, or if needing higher notes, is also on the 7th fret.
An inserting thing is that the barre of the low 3 strings creates the 'police chord' of stacked fifths so is 'symmetrical' in 5ths on the lower string and by just adding a finger on the D string to this barre, you get a minor or major arpeggio.
Tuning in fifths is standard on smaller string instruments like violin or mandolin because you can stretch that far, but on guitar, there are awkward jumps. On bass movements though, largely in 5ths and things, it seems to be a useful thing. Again though, it is not really for scale or strumming chord kinds of things but bass lines with chords or melody above.
There is a logical consistency to thing in 5hts, every interval is the same 'shape' and ll that and across strings, but for playing bigger chord formations and the like, I found it far too impractical on an instrument as big as the guitar. That is an interesting site though.
Joni Mitchell has obviously used any number of tunings and to great effect really, that she is using the VG system is an interesting thing.
I have been and still considering some DIY like digital solutions and this guitar was built to accommodate some of that. Hence the 'hex' project where one could take selected strings and digitally pitch shift them down an octave with or without the original pitch to get into that 'bass' range...even in standard tuning. It's a different thing, but at least one could use standard tuning and guitars but fill that rich low range. A work in progress, but there is still something cool about open tunings.
An interesting quote for that TK link to 5ths was...
There are elements of that for me I guess.
Largely I just can not reach the kind of range with the solo guitar thing that I'd like to hear, everything needs to be in 'close voicing' to some extent. Retuning does make for interesting uses of the open strings and more separation and range between the bass and other strings as well as the ability to reach notes otherwise not possible. The lowered strings also sound 'different' too, a very rich effect from the loose strings.
Tuning all the way down to A as PM does on his baritone seems a little ambitious for a standard guitar, but wondered whether one could do similar by moving around a fairly standard set tuned to B perhaps.
The things like the VG system are interesting for that and seen it demoed, it is not quite the 'same' and really I'd not seen anyone make that much use of the huge range of possibilities such things offer. Way out of my price range though I have to say LOL. Gibsons 'robot' guitar thing also ahs similar possibilities and the fender V thing also does things with tunings...still, not seen them put to a lot of use. Mechanically the trilogy is also in a similar ball park and the best I could do. I'm interested in taking this further in the future.
There is the option I guess of simply adding more strings like charlie hunter and others have done. Quite a few 7 stringers about though I've not heard it being used in this kind of way, just to get a super low 'heavy' sound which was in vogue a'la Korn et al with few exceptions...it's a bit unwieldy and would require a special instrument.
Phil Keaggy is also an interesting character, DADGAD has some fabulous music written for it and the guitar can tune to that easily. Lawrence Juber does a lot of things in that tuning that I've tried. It's popular with those celtic kinds of traditions...lots of octaves in it!
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Bur always there is that 'remapping' thing that is surprisingly hard to think around, perhaps harder when you know the fretboard so well as it is like 'translating' and so adding another layer of thinking..you know, I want a low E, the string is tuned to C, the note is now on the 4th fret...doh...the need for the note is passed!
Pat Metheny's approach inspired me though, keeping it standard effectively, the 'mapping' is the same but he 'thinks' in terms of three two string guitars. The bass or cello, viola and violins, the arrangements often keep the melody in the middle rang with higher harmonies 'above' the melody or harmonies. Hard to get used to the high strings being in the middle of the guitar, but it is an impressive sound. I might try that on a cheap spare I have that is never used and see what it is like, at least I will know where the notes are.
Thanks for all the input...when the internet is back to speed, I'll look into those links even further and see where they lead!