yozhik
Oud Addict
Posts: 44
Registered: 11-13-2017
Location: Sweden
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What densities to use when calculating tension of various string types (Pyramid PVF, Pyramid, silver wound, Aquila nylgut, etc)?
I am looking to put together some different string sets to experiment with the playability and sound of different tensions and materials on my
ouds.
In order to estimate string tension I will use a calculator (e.g. Arto's String Calculator), which requires knowing the density of the strings.
What densities should I use for the following string types?
Pyramid plain PVF (lute strings)
Pyramid rectified nylong (lute strings)
Pyramid silver wound (lute strings)
Pyramid copper wound (lute strings)
Aquila plain nylgut (whatever material is used for the trebles in the current Aquila Arabic standard tuning set)
Aquila copper wounds (red-colored copper wounds from the standard Arabic set)
Arto's String Calculator lists the following examples:
1000 Kg/m³, nylon
1791 Kg/m³, "carbon"
Does this mean I should use 1000 kg/m³ for the "rectified nylon" and 1791 kg/m³ for the Pyramid PVF?
I searched the forum and found some posts where 1.3 gm/cm³ was used for plain nylguts. Is this correct?
And what should I use for the Pyramid and Aquila wounds?
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Brian Prunka
Oud Junkie
Posts: 2939
Registered: 1-30-2004
Location: Brooklyn, NY
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Pyramid sells a slide rule-type calculator for determining their string tensions.
PVF is presumably reasonably correct. I've gotten different results on nylon, as there are multiple formulations and rectified nylon may have a
slightly different effective density than plain extruded nylon.
Aquila claims their strings are effectively the same density as gut.
It's close but not exact and they've reformulated the strings more than once. But using the gut densities is reasonably close. I think they also had
a conversion table up at one point.
There is no system for converting gauge to density with respect to wound strings, even with the same manufacturer. There are way too many factors:
core material/density, winding gauge, winding materials, etc. For example D'addario's .025w string is lighter than their .024w string. Pyramid
doesn't even publish gauges for their wound strings for this reasons (though you could measure them, but it would be meaningless data really).
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jdowning
Oud Junkie
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Registered: 8-2-2006
Location: Ontario, Canada
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To add to Brian's comments.
I use the convenient Pyramid string slide rule calculator to select their strings but I also posted, some years ago this forum, a set of the original
Pyramid string tension tables (with permission of Pyramid) that might be of some use - particularly for their composite wound strings - if one does
not have the slide rule.
http://www.mikeouds.com/messageboard/viewthread.php?tid=4299#pid280...
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Brian Prunka
Oud Junkie
Posts: 2939
Registered: 1-30-2004
Location: Brooklyn, NY
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Mood: Stringish
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Thanks for posting, John. These tables are more than adequate for oud calculations.
As you've noted previously, for tensions to 'feel' equal, they generally will reduce gradually in the bass courses. However, after much
experimentation, I've concluded that the ideal set is a bit more complex.
The single low bass course I like to up the tension a bit, since it is quite a low note for the length of the oud and it seems to balance a bit better
and produce slightly cleaner overtones. the 2nd gg course I like a bit lower tension because it keeps the nylon from sounding too 'tubby'. But
different ouds can respond quite differently and one really needs to experiment and refine the choices over time.
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alchemy
Oud Maniac
Posts: 57
Registered: 11-30-2014
Location: Buenos Aires, Argentina
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If you search online, you'll find a newer version of Arto's calculator which includes density for nylgut at https://www.cs.helsinki.fi/u/wikla/mus/NewScalc/
Unfortunately, it was coded in a different technology (Java) which most browsers don't support for being very bad at performance and security, but if
you install Java you might be able to run it (try different browsers).
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