MIMF

I would like to start a thread about building guitars tuned in fifths.

I've always liked to have the possibility to play in the bass and guitar register and I always felt a little bit uncomfortable with the irregularity in the conventional guitar tuning. I've tried an extended guitar tuning a la Charlie Hunter (p.a. 8 string: E A D - A d g b e' or E A D - d g b e'), but although it gave my an extended range, I wasn't satisfied with the tuning. I've also tried tuning up in perfects fourths (p.a. E A D G c f Bb Eb,), but it didn't gave me the opportunity to play 4 or 5 string chords.

In this search I've tried an all fifths tuning on and off and now I'm pretty satisfied with the results.
Of course there's a lot to say about the (dis)advantages of this tuning but that will not be the focus of this topic.
Because of the wide range which can be achieved with only 6 or 7 strings, there are several technical issues to be dealt with.
What strings gauges to use? What pickup to use? What stringlength(s)?

I'm not the first to explore an all fifths tuning for guitar, Todd Keehn of TK instruments even sells guitars fit for a fifths tuning. But I would like to see if I can stretch the range a bit more.

I would gladly recieve feedback and comments.

Right now I'm building my first prototype.

I've used my 7 string guitar which I build recently as a reference ( http://www.mimf.com/phpbb/viewtopic.php?f=4&t=1324) .
This has a 760 - 660 cm stringlength.
My goal is to tune the guitar from a low C (one step above the low B of a five string bassguitar) to f# (two steps above the high e string of a guitar). So that will be: C G D A e b f#.

I started off with a 0.130 gauge B string and as a rule of thumb I used the following formula to calculate the next string gauge next string gauge = string gauge* 2/3.
After trying several string gauges I've noticed that the bass side needs heavier strings (more tension) then the treble side, so I've come up with the following gauges for now: 0.130w, 0.080w, 0.055w, 0.032w, 0.022, 0.014, 0.009
When tuning up with these gauges the (bass)strings where a bit loose, but this was resolved by tuning the strings one step up.
In my prototype I want to use a 810 - 710 cm stringlength to compensate this.

I want to use a 6mm (nut) and 10 mm (bridge) stringspacing (spacing from side to side of the strings).

I'm using birch plywood for the body and neck.
I want to make my own Low Z single loop pickups (one for the 3 bass strings and one for the 4 treble strings).

Since I build a variety of both traditional and experimental instruments I may be able to help.
One of the big concerns I see in your post so far is balancing the tension of the strings.
It is important to have somewhat equal tension thru all of the string courses, otherwise over time the instrument's neck will warp in the direction of the greatest pull.

http://www.daddario.com/DAstringtension ... 5b1387351c

This chart will allow you to determine what string gauge you need for your scale length, tuning, and desired tension.I find it to be a wonderful resource that I'm referencing on a regular basis.

Greg, thank you for your useful link. I'm going to use a smaller gauge B/C string.

Right now I like the "heavier" feel of the three bass strings (C' - G - D), so if possible I would like to maintain that setup.
Roughly the tension of the bass side eqeals the tension on the treble side (see table below: I've used nickelplated strings as a reference).
And the three bass strings are on one half of the neck and the four treble strings on the other half.

Will the neck warp? Does it need extra reinforcement beside the truss rod?
I want to use birch plywood and a martin style single action truss rod. The neck will be app. 1" thick.

I remember that Greg Robinson said that he's using string sets with extra heavy bass strings (but I can't remember the thread).
How does these necks hold up in time?

Hans


Pitch String gauge Unity weight Stringlength Frequenty Tension (N)
C' 0,125 0,0027481 31,968503937 32,7031956626 138,3695177808
G 0,08 0,0011602 31,2992125984 48,9994294977 125,7084920722
D 0,055 0,0005481 30,7086614173 73,4161919794 128,3359020377

A 0,032 0,00019347 30,157480315 110 98,0780883919
e 0,022 0,0001072 29,6062992126 164,8137784564 117,5798629896
b 0,014 0,00004342 29,0551181102 246,9416506281 102,96904566
f#' 0,009 0,00001794 28,5433070866 369,9944227116 92,1731136313

For what it's worth, Hunter's setup has changed over the years as his style and use of the 8-string you reference have changed. For a while, he began tuning up a half step (F...f). This was done in search of more tension in the bass strings. Now, he's tuned up a minor third and dropped the highest string (G...d, or like capoing standard tuning at the 3rd fret), again in search of more tension in the bass strings and a realization that he didn't need that top string. You may find you want/need to do something similar in order to balance scale length playability with string tension.

Jason, Thank you for your reply.

My biggest concern is getting a good sounding low C string.

Charlie Hunter is playing a 29" - 25.5" guitar with a G as the lowest string (as you said). Todd Kheen (http://www.tkinstruments.com/5ths_tuned ... d_bass.htm) is building guitars with a low G using a 0.075 gauge string and a 27"- 25" scale lenght.
I think that my style of playing (using my thumb for playing the bass strings) requires a little more tension, like the CH setup.

For now I'm using a scale lenght for the bass side which is roughly a regular bass guitar scale lenght fretted on the first fret ( 34"/2^(1/12)= 32.1" ), I'll hope that this will result in a (chord) playable neck. If not then I have to rethink my tuning (p.a. six string: Low F to high E like a six string (electric) cello).
Hans

Make a mock-up of the neck (cardboard) with the scales you have in mind. Then "play" it and feel the reach you'd need to get the job done. When I was planning a Hunter-esque guitar (which never materialized, alas), I started with a 30" bass scale. Glad I didn't actually cut any wood, because after holding the cardboard cutout and attempting to fret anything, it would have been too long to play comfortably.

I have built more jigs than guitars,
but it seems to me that your could make a proto type like a pedal steel,
to test scale vs string tension and string gauge use fairly easily and cheaply.
You could then use your data when you satisfied with the tuning and set up build your project based or your test results.

I've made a mock-up of 9 mm plywood and "played" it, I think I'll be fine. My hands are pretty big and with most chords grapping is made easy due to the fanned fretboard (the frets are the most tilted at the beginning and end of the fredboard).
For now I'll continue with the 810-710 mm stringlength.

thanks for the advice.
Hans

Interesting project. The tuning is that of Fripps Guitar Craft projects. Unlike the guitars he commissioned from Ovation, you are headed the right direction with multi-scale. As near as I can see twist warping over time could be fought with carbon fiber rod reinforcement on either side of the truss. Some would be tempted to dual truss rods, but I believe that is too much wood to remove in a neck no wider than a guitars.
My last multiscale was 27" & 24.75" and landed just within my comfort zone. Took a few weeks to get used to it, but now it's one of my favorites. I'll be interested in seeing your output.
Have you come across Guitar Craft? http://en.wikipedia.org/wiki/Guitar_Craft They are a defunct project now, but the California Guitar Trio is one of the fruits it bore.

I'm familiar with Fripps tuning (NST). I've wondered why he is exploring different tunings one the one hand, put kept on using a standard guitar (with parallel frets) on the other, but maybe he just didn't came across the multi-scale concept (although it has his history).

As for my project: winter has made a comeback in The Netherlands so I have to put the building on hold until the temperature rises again.
I'm not sure what to do with the neck, I've allready made a neck with a trussrod channel in de middle.

To be continued...

Hans Bezemer wrote:I'm familiar with Fripps tuning (NST). I've wondered why he is exploring different tunings one the one hand, put kept on using a standard guitar (with parallel frets) on the other, but maybe he just didn't came across the multi-scale concept (although it has his history).

Well Fripp came up with that idea in 1983. When were the first multi scale guitars made? Novak filled for his patent in 1988.

it might have helped Fripp get the high b string he originally wanted.

We have discussed multiscale instruments here for years. They are not new at all. A multiscale instrument was depicted in a book published in 1619. Despite this prior art, a US patent was obtained in 1900 on a multiscale instrument, and Novak patented it again in 1989. Neither patent should have ever been approved because of the prior art, but the patent review process is poor at best. Here is some more history: http://en.wikipedia.org/wiki/Multi-scale_fingerboard

Yes Jim,I agree.
Anyway, Fripp laid the path for a all fifths tuning on guitar.

I'm thinking about making a angled headstock, but don't really know how to deal with the angle in the nut.
The difference between the bassside and trebleside is around 2".
Can I bevel the fretboard behind the nut?
or make a double angled headstock like Tristan did? http://www.mimf.com/phpbb/viewtopic.php ... t=20#p7077

I've been experimentating with different string gauges.
I like to have some more tension on the bass side then on the treble side (as is the same with a regular bass and electric guitar).

When the diameter of the next higher string is roughly 2/3 compared to the diameter of the lower string, the tension is even (because of the fifths tuning).
But this would result in either a floppy bassside or a unbendable of even untunable trebleside.
I accidently used the number phi (0.618) as a rule of thumb for calculating the string gauges and this provided a nice balanced stringset.
I've now to setups, and both work well:
7 string 760-660mm stringlenght: Bass C-G-D-A-E-B-F# treble 0.145 --> 0.009
6 string 650 mm stringlength: Bass G-D-A-E-B-F# treble 0.110 --> 0.010

Hans