Thank you both, Mimmo and Alexander, for your very complete answers
Anthony
Le 18 févr. 09 à 13:20, alexander a écrit :
The degree of twist is decisive, when all the rest is equal for a
given gut (treatment, animal of origin, etc) for the breaking
strength. I would hazard that .44 is made with the same twist by
the same maker as .42. Which means if your instrument can take it,
it will substitute for .42 just fine. .44 will be equally strong.
The need to change the twist degree arrives at other diameter
ranges, it appears.
Interestingly enough, the working string length of historical
instruments, drops slightly in relation to the mathematical
formula, which means that, as Mimmo pointed out, the string twist
was higher for the longer instruments.
alexander
On Wed, 18 Feb 2009 12:29:08 +0100
Anthony Hind <[email protected]> wrote:
Dear Mimmo and All,
If I have understood you correctly, there is a sort of
contradiction : as gut becomes thicker, it must be treated to make
it more flexible (higher twist and possibly softening chemicals), or
else it becomes inharmonic. The more flexible it is, for a given
diameter, however, the less tension it can stand (the Breaking Index
drops). Thus it is not the thickness itself, but the way thick gut is
treated that makes it break quicker than thin gut?
You say the Index of a modern gut string is 260 Hz/m, but this is
only true true for the range of lute 1st string gauges.
"I mean 38 till 46 mm (more or less), where strings are made with a
very low twist and gut is made harder by chemicals."
Does this mean that it is possible to substitute say a 44 treble
anywhere where it is safe to use a 42 treble, keeping exactly the
same breaking point in Hz; or does your "more or less" imply that
even for "38 till 46 mm" there will be a slight difference in twist
or hardening, which could mean the 44 would be less strong than
the 42?
Of course I realize that such a substitution would increase the
playing tension, which may or may not be an advantage.
Regards
Anthony
with a 44 treble
Le 18 févr. 09 à 07:21, Mimmo Peruffo a écrit :
Hello guys,
Just an observation: the suggested average of the Breacking
Index of a
modern gut string is 260 Hz/m. However, the full range of
modern lute
strings ranging between 240- 300 Hz.mt.
This is true for the range of lute 1st string gauges. I mean 38
till
46 mm (more or less), were strings are made with a very low
twist and
gut is made harder by chemicals. The Breacking Index drop in the
case
that we are speacking of thicker 1st strings, were they are
made with
more twist than the lute chantarelles.
Example: on the 1st bass gamba strings the Breacking Index drop
of a
semitone-tone than the lute 1st strings.
In fact this is function of some technological things: the twist
quantity and the use (or not) of some substances ables to do gut
harder
etc etc.
If we go in the range of the violone 1st strings the breacking
Index
drop again and again because such strings are made very very
high twist
and without any chemical tretment able to do gut stiffer. This
is why,
in my wiew, the calculated Working Indexes (the product of the
string
scale X the supposed frequencies of the 1st strings) of the bowed
instruments in the Praetorous tables drop step- by -step when the
instrument became longer. So on Violins we are in the average
of 210
HZ/mt while, on violones, we drop to arround 180 Hz/m only.
Ciao
Mimmo
alexander ha scritto:
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