I built a 63+ cm. length lute some years back, actually a "bastard" lute
in that it was Music Maker's "flatback". I had the breakage problem with
the chanterelle also - I was pitching to A440 and tuning to G. Musical
nylon would last a few days, nylgut would break almost immediately. I
went to a sporting goods store and chatted with the fishing department -
they gave me about 10 feet of nylon "leader" line to try. It worked, I
have had no breakage in ten years.
The Aquila article is interesting, but perhaps overly technical as it
doesn't start with the basic principle. Please pardon my simple primer,
I'm sure it is obvious to most of you - but I had played guitar for
years before I realized this.
A string (or a rope, or a structural wire/rod) breaks when the stress on
it exceeds the tensile strength of the material used. We stress a
musical string when we tune it up to the tension for the desired
pitch/frequency. The frequency of the vibration is a function of the
combination of string (or rope - think of the shrouds of a sailboat
humming in a strong wind) length, the tension, and the vibrating mass of
the string.
The mass is a function of the density of the material (mass/weight per
unit - i.e., lbs./cubic inch, grams/cubic cm., etc) and the number of
units (length, sort of). I say mass/weight for the very technical, they
are the same in our gravity. Notice that it is a cubic measure - a long
thin string will have the same weight as a short fat one.
The tensile strength is also a function of the specific material, and it
is normally measured in weight per cross-sectional unit (i.e.,
lbs/square in., kilograms/square cm.). A thin string will break when
supporting less weight than a fat one because of the greater
cross-sectional area. We normally measure the tension on our musical
strings using pounds (or a metric weight), but that is shorthand - the
newton is the general measure.
My revelation (satori?) when I was building that lute was that, given
the material and the length, any gauge of string will break at the same
pitch. The thicker the gauge the stronger the string, but also the
greater the vibrating mass. The greater vibrating mass requires greater
tension on the string to bring it to pitch. It happens that the
competing factors (the square measure of cross-section that defines
tensile strength and the cubic measure of mass) meet at a point we can
call the "breaking pitch" for a given length and material.
This, of course, applies to monofiliment strings, wound strings add mass
without changing the core strength, but that is another matter.
Best, Jon
On 1/1/2013 3:02 PM, Paul Daverman wrote:
I am building a 10 cs. lute per Robert Lundberg's plans (10-cs
Renaissance Lute, Dieffopruchar 1612). I am to the point where I have
begun looking at strings so that I have an idea of diameters, etc. As
this is my first lute build, I am looking at Nylgut and am looking to
tune to AD0. One of the suppliers to which I have inquired has said
that in A440 tuning, they have no strings at 65cm length that can take
the tension for the chanderelle (and that no gut could either.) He
said that the instrument was probably meant for A92 and while he could
supply strings in either tuning, I'd have to look elsewhere for a
string for the chanderelle if I chose A440.
I am wondering if any of you can talk to this topic. Would I be over
stressing the lute if I tune to the modern tuning of A440? Would A392
have been the intended tuning or maybe A415? What other repercussions
of tuning one way vs. another should I know about? My music theory is
a bit poor - is the difference between going from A440 tuning to A392
really any different that transposing down a (??) major second? Any
word to help get all this straight in my mind would be appreciated.
While I understand that "pitch" is all relative, I'm having a difficult
time getting my arms around the practical understanding of what I
should do for stringing. Thanks.
Paul
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