Official Luthiers Forum!

How did the standard gauges come about? For example, D'Addario lights range from 23.3lbs on the plain strings, to 30.5lbs on the D string. but then the low E is in the middle at 26lbs. Mediums follow a similar pattern, ranging from 26.3lbs for the B to 36.8lbs for the D.

Those are huge percentage differences. I assume string companies would have done tons of testing to figure out the best sounding and feeling strings on a large number of guitars from different manufacturers and players with different styles, but is there any rational explanation for the conclusion they've come to? And is it really the best thing for well balanced hand built guitars?

Or looking at that from the opposite angle, should we be trying to build guitars with a particular uneven frequency response to counterbalance standard string sets? This seems particularly true for classicals, where the G is usually much lower tension than the rest. But why is it? The G almost always sounds weak and tubby on factory classicals. I haven't had the opportunity to play a high end hand built classical, but does it turn out that with enough skill, the low tension G actually sounds better than a medium tension G on a more evenly responding soundbox?

I'll be doing some experimentation on this myself, but in the meantime, discuss!

This is from my reading, so definitely second-hand, but ...

I believe that part of the reason is for playability. The stiffness of a string, i.e. the resistance when fretting it, is a product of both tension and thickness (or maybe mass, but thicker strings of the same type are more massive than thinner ones). For the same note, a thicker string also requires higher tension, so the stiffness "feel" increases in a non-linear fashion. Thus if all the wound strings (say) were at the same tension, the lower strings would need to be thicker and so require much more pressure to fret. This would make playing a challenge.

With unwound strings there is also the problem that there is an upper limit on how thick you can make them and they still work. I think the unwound G is pushing that limit. A higher tension string might sound better, but would need to be too thick (and might also be unplayable for the reasons explained above).

"I'll be doing some experimentation on this myself, but in the meantime, discuss!"

Another thing to look at would be the overtone series generated by different strings. As strings become stiffer the upper partials tend to go sharp. When strings aren't matched properly the different frequencies of the partials generated create dissonance. That is the reason a grand piano can't play in tune with a spinet. It could be that the strings matched for overtones require different tensions. But then again they may not pay attention to that at all.

Manufacturers are gradually making even tension sets available.

I've been playing even tension sets on acoustic and progressive tension sets on electric for many years and I'll never go back to traditional sets.

I've made my own string tension spreadsheet but website calculators are readily available.

Making your own sets is a must when playing multi scale instruments.

There's another string parameter that matters; the 'impedance'. This is, in a sense, a measure of how hard the string can push on the bridge at a give amplitude, and is proportional to sqrt(tension times mass). If you make the string have equal tension, so that they feel the same when you push them down, the impedance varies a lot from string to string, so they will tend to sound more uneven. Most string sets seem to be a compromise in this respect.

I'd love to see measurements done on this issue.

I've usually found that the string gages I'm substituting in to even out the tension are taken from the next lighter or heavier sets.

I've yet to experience any noticeable unevenness in output between strings.

It would be great to have output measurements to compare traditional sets with even tension sets.