Made a jig to measure the tension from different strings using a hanging scale capable of 100 kg. The information about tension is one thing the string makers seldom talk about. And if they have measures the mensur/open string length used is not mentioned or hard to find.
I wanted to really know if low tension 0.12 Newtone Heritage had about the same tension as Newtone Masterclass 0.11 and so it was. NH 0.12 was 60 kg and NM 61.5 kg.
The measurement was made with 63 cm mensur and standard tuning. Using the NM set I found a pretty linear function with about 2 kg added tension for each added cm of open string length. 60 cm mensur gave 55 kg in tension and 65 cm mensur 65 kg.
so the tuner just picks up the acoustic vibrations of the strings?
also, most of the big US string companies do publish string tension vs gauge/pitch/scale length charts.
Yes, I can tune the strings using the vibration in the head just like the clip-on tuners. Many makers do publish the tension of the strings but not all and not the strings I happen to use. I was also interested to know how different open strings lengths affected the tension. Can be handy to check out odd tunings too.
I love geeky stuff like this :-)