Jaroslaw and Martyn
I believe the difference in calculation comes from Martyn using a
stiffish high twist (rather than a rope). This can possibly be pushed
through quite a narrow hole, where a flexible rope would not go through.
Mimmo is taking the calculation for a rope diameter as being 80% of
the size of the hole, as Segerman seems to have said. Perhaps,
Segerman's ropes at that time were unsmoothed, perhaps not.
Then, we know that ropes have a higher degree of flexibity than stiff
gut. Thus when you raise the rope up to tension, it will become
thinner than its original size. So it will be thinner than 80%,
perhaps around 70% to 75% (if it began at 80% of the size of the lute
hole).
Now, this would be what would happen, with the type of stringing that
Satoh uses (Pistoys). However, Martyn seems to be using a stiff gut
high twist of 1,4 that he thinks will go through a hole of 1,5mm.
Have you actually tried that Martyn? Now according to Charles
Besnainou, inharmonicity is caused by the stiffness of the string at
the bridge and the nut. I simplify, but the sound waves encounter the
greater stiffness at the nut and bridge end, and some wave forms are
returned out of phase, and these partially cancel the initiating wave
form (particularly the high frequencies) givin inharmonicity.
If the high twist and the rope are at normal high tension, the result
will be far worse for the hightwist, as it will be stiffer. However,
perhaps you can lower the tension more on a high twist, before it
loses its ability to vibrate.
As you lower the tension, so the stiffness will presumably decrease
at the nut and the bridge. Perhaps at a very low tension this means
that the hightwist is not so inharmonic as it was previously.
This sort of thing can be measured. I will ask Charles whether he has
done comparative studies of such strings at lower tensions.
Martyn, what is the sound like of your high twist at 1,5Kg? Does it
sound good. Could you make a recording for us? Have you actually
tried using a 1,4 string with a 1,5 hole?
More importantly, even if this CAN be done, is it comfortable? Is it
hard to push the string through (even if it is possible)? Would you
want to do that each time you put a string on your lute?
If this is not the case why did they not make slightly larger holes?
Have I in any way twisted your hypothesis. I tried to state what I
understand, and the possible consequences. Please let us know your
thoughts.
Anthony
Le 8 juin 08 à 15:35, Jarosław Lipski a écrit :
Hi Martyn,
I just talked to Mimmo. He explained that the tension of 0.9 till
1.2 Kg
came out from mathematical calculations made by Ephraim Segerman
considering
the bridge holes of surviving lutes. He calculated some 1.2 till
1.5 Kg. but
this was made considered the density of a low twist gut (that
unstretched at
all). He made new calculations considering the only alternative to the
loading of a gut that is stretchable and less dens roped string.
This is why
tension would be around 1 Kg each bass string on such historical
lutes.
Best
Jaroslaw
-----Original Message-----
From: Martyn Hodgson [mailto:[EMAIL PROTECTED]
Sent: Friday, June 06, 2008 12:45 PM
To: 'Lute'; Jarosław Lipski
Subject: Re: [LUTE] Re: [LUTE] Re: [LUTE] Re: Double headed
12c/loaded/Demi-filé
I don't know where Mimmo gets the tension of 0.9 - 1.0Kg from, but
as an
example: take a Dm tuned lute at 68cm (with top course f' tuned as
reasonably high as it will go without excessive breakages allows a
pitch of
A415) with a bass string hole allowing a max string of diameter of
1.4mm
gives a string tension of around 1.45Kg.
MH
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