Official Luthiers Forum!

hello to all. A newbie to the forum and great to see such a positive and active place to discuss the craft. I am tossing the idea of building a 5 string mandolin with a scale length in the ball park of 16", which happens to place it in the mandola category. Considering this, I am comfortable in knowing that it would support the tension of a FCGDA tuning (one fifth below mandolin) however, my thinking is to craft something that is also flexible enough to support the 5 string tension of CGDAE tuning. I know the odds of the E string possibly having to much tension in this context, so I was thinking of what could maybe be a middle ground, to achieve proper tension and overall tuning flexibility (moving between FCGDA and CGDAE). Does a 15 3/8" or (38cm) scale length make more sense, or does this 5/8" (8cm) not have as much impact on the issue of E string tension. (my dilema is that anything shorter than say 14 3/4" might create a floppy C string and certainly losses the flexibility to tune in a FCGDA).

Once again thank you for allowing to be a part of the discussion and asking my quesiton.

Welcome to the OLF, Matt (I assume your name is Matt). You are way over my head, but someone will probably entertain your questions. I think we have a few mandolin builders around here.

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Waddy

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I'm of the opinion that the scales of the standard instruments are what they are for a good reason. A five string mandola/mandolin will probably have problems with either the low strings or the high strings or both. If you make a mandola body and neck and try to add a high string to it you will be near the limit on string tension. If you make a mandolin body and try to add a low string to it, it would probably be too floppy and give unsatisfactory tone. Cutting the baby in half and trying to use a body and scale that is in between could help to address the problems but my guess is that scale lengths where the bass strings are too loose or too weak sounding will overlap with the scale lengths where the high strings are too tight and break or cause damage.

A five string instrument that was easy to play, robust and sounded good would be the standard if you could build it. The fact that it isn't is a big clue that making a satisfactory instrument is going to be difficult.

A counter argument exists in a baritone guitar that Al Carruth made. It isn't nearly as long as other baritones but it sounds wonderful. When I heard Ed Gerhard playing it, I kept thinking, "Why aren't all guitars made with this scale?" It had a resonant bass and yet the high strings sounded bright and strong.

Matt

This topic came up a while ago on a Mando forum. Im going for f@nned frets as the solution. Also check out an instrument called the Opharion ( http://www.nationalmuseet.dk/sw48918.asp ) and Mandolin Magazine issue Vol 9 No 2, the article by James Condino. I like the idea of as five double course instrument tuned in fifths as well, the best of a lot of worlds. I will be using the Opharion plans for a future build but any number of body shapes would be cool, eg F4 or even a Vega Cylinderback.

I will disagree Mike as there have been lots of ideas without the techology to support them. There is gossip that the Opharion never made it because of the changing of a steel concession in 17thC Germany and the availability of metal that could handle the tension as strings dried up. I dont know if that is true but the instrument makes as lot of sense to me. Modern strings, bracing etc make it more feasable. The idea even got patented by a 20C opportunist!

Sebastiaan

Yes there is the chance for a floppy low C on a lower scale length and a tension issue on a longer scale length. The fan'd frets idea is an awesome movement, they look pretty cool as well....though not sure if my mathmatics would be up to snuff in that department...at least until they come out with a fanned fret calculator...lol.

I am thinking that a 15 3/8 scale may resolve the issue, though my concern is,,,does 5/8" make that much of a difference???? That I am not so sure of.

Matt,

Try FretFind 2D or else use the calculators provided by Stewmac and the like. BTW the parallel fret doesnt need to be fret 12 which FretFind 2D suggests. With my amateur playing (mostly lower on the neck) Im going for fret 7 as the parallel fret. Im making two fret spaced rulers which Im placing side by side to see what it looks like and which would be a better parallel fret.

Im not sure 5/8" would make that much difference but then I am yet to build one. My experience is in mando's and no f@nned frets yet. The literature suggests that string gauge choice is important as well. Maybe 14 3/4" on the "E" and 16" on the "C" might do it. Other considerations would be soundboard thickness and graduation and the configuration of bracing. Im sure other mando builders on the list will add their comments.

In the end there is only one way to find out. Being an amateur I dont have customer expectations or the weight of tradition to hold me back. Aint it great! Still, it will take 12 months to test the ideas.

Noob question: Are fanned frets basically the same as saying that each string (or course as in a mando) has a different scale length? Is the saddle/bridge at an "unusual" angle to accommodate the increasing scale per string?

Yes, google fanned fret and you will find lots of piccies as to how it works.

There is some stuff in the archives on fanned fret guitars too. I recall that Dave White built a beautiful one, and there was discussion on how the fan was determined. Not sure if it was in the same thread or not.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Matt,

Building a stringed instrument that can go from any tuning, to a fifth above or below that tuning in my opinon can't be done.

As an experiment tune any string on a instrument down a fifth and notice how loose it becomes, don't even try to tune it up a fifth.

This would be the same problem on a Fan fret also.

There is a range in scale length that will work for a given tuning,
and string gauge sizes are important for whatever length of the range scale you choose.

A change of 5/8" in scale length (16"--15 3/8") would vary based on string gauge and the note it would be tuned.

Designing a soundboard and bracing pattern that would perform well
with a fifth of tuning range, falls in the same can't be done category

Hope this helps.

Tom

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