Freq change- string under const tension

[Beaubello]

Given a nylon guitar(e.g.) string stretched across 2 boundary nodes, a makeshift "nut" and "bridge" on a workbench. At the bridge end the string is tied to an overhanging weight in order to maintain const tension ( unlike a string instrument where the pegs are free to turn gradually and permit a change in tension with attendant detuning ). How would the frequency change as a function of temperature and humidity ( in say 20 - 80 deg F )? Would frequency change be due to any significant extent to a change in string mass/L, largely a result of the varying speed of sound in air or to some other cause? Similarly how should strings of other various materials compare with respect to their frequency stabilities?
Finally with regard to string instrument application might such an investigation have practical implications for choice of string material to better hold tuning or is string detuning the overwhelming result of the change in string tension from turning pegs?

 

[matthewgill]

The string tension is not lost via the tuning pegs, unless they are of very very low quality. On a guitar for example, they can be locking. It is common that the wood of the instrument expands/contracts with temperature... pulling the strings with it. Sometimes when strings get old they don’t hold there pitch quite so well, but this would be the strings' fault not the tuning pegs', something to experiment with there?