Big string bends on acoustic and staying in tune

[Jimmy Recard]

Originally Posted by earri

This is exactly correct. In my experience, after some time I reach an equilibrium (for lack of a better word) where most, if not nearly all of the slack has been reduced from the system. My guitar solidly stays in tune (bends and all), absent environmental changes. The thing is, I only reach that point after having had the strings on for some weeks (usually 4, or more), so it requires long lasting strings (currently Monel Retros).

My E10SS is currently in that state. I played in a jam circle last week and wailed on it for 3+ hours.; never strayed (at all). Still in tune the next day, and for 3 days thereafter until a change in the weather required a slight retune some days later.

My question Fazool is why do the strings begin to not hold tune when they have aged significantly? That's one indication for me that it may be time for a change.

Great answer Fazool.

Strings work in the elastic region, as fazool said, but over time they work harden due to playing and age (and likely also experience some creep). Once they work harden their elastic ability is reduced and they become brittle. Also there is a stage between transitioning from plastic to elastic and breaking when the string is permanently deforming. Old work hardened strings are more likely to be deforming as they've lost some of their elasticity.

[Jimmy Recard]

Originally Posted by Kerbie

I've never had a tuning problem from bending strings. Most of my bends in the blues are pretty small, maybe a 1/4-tone or so. How much are you bending the tone?

Like Silly said, I would think sufficiently-stretched strings should handle bending just fine.

Bending up one whole step while soloing, generally around the 8th to 10th fret.

[Kerbie]

Originally Posted by Jimmy Recard

Bending up one whole step while soloing, generally around the 8th to 10th fret.

Oh, OK... that's more than I prefer to bend on an acoustic, but it still seems to me like it shouldn't be more than a very minor problem.

[rogthefrog]

Originally Posted by Silly Moustache

most of us have to quickly and carefully check tuning during applause after every song anyway.

That tip is only valid for those who get applause.

[fazool]

Originally Posted by rogthefrog

That tip is only valid for those who get applause.

hahahahaha

[JeffreyAK]

Us physicists like to do experiments to get real data. So here is what I did out of curiosity, to see what happens to a brand new string when we "break it in" by stretching it out.

1) Marked two tiny black spots on a new Ernie Ball 0.010" string with a sharpie, placed so that they would wind up between the nut and saddle on my Strat when I mount up the string.
2) Measured the distance between the two spots as precisely as I could, which is approximately a tenth of a mm for changes and approximately 1 mm absolute accuracy, using a meter stick with two good metal rulers with 0.5 mm increments taped to it. The initial separation was 556 mm.
3) Removed my old E string and mounted the new one, being careful not to rub off the sharpie marks.
4) Tuned the string to E, 329.6 Hz.
5) Stretched the string vigorously with my fingers. I noted that the tuning dropped a half-step to Eflat, 311.1 Hz.
6) Retuned to E and stretched again. The tuning dropped a little bit.
7) Retuned to E and stretched again. The tuning did not drop.
8) Removed the string carefully and remounted it on my measurement device. The final separation was..... 556 + 0.1 mm.

So any real deformation of the string was at the limit of my ability to measure, and approximately 0.018%. This compares with the change in frequency due to stretching (5.6% after the first stretching routine), and the required decrease in mass per unit length required to explain that frequency change (twice that, if I did the math right).

Conclusion: A string can indeed stretch and deform a bit, but what I measured can't possibly account for the full half-step drop in tuning I heard. In fact it's nowhere close.

So what is changing? It seems unlikely to be the tuning peg, since the string was wrapped nicely and tightly. My guess, it's at the ball end somewhere, but that's a guess.

If a string doesn't deform when it's brand new and just installed, it certainly won't when you bend it up a half step or two. But it's conceivable that whatever is slipping when you break in a brand new string, could slip a bit more when you bend it up, particularly if it's still relatively new and if you haven't gone through a stretching routine to get it to hold a stable tuning.

[sirwhale]

Originally Posted by Wyllys

The probable cause is the string hanging up in the nut. The probable cure is to put a little graphite in the slots.

+1

Getting stuck in the nut, you bend it pulling it towards the bridge and it gets stuck again.

Graphite first, but itf it still happens, you need to look at widening/smoothing edges of the nut slots.

[fazool]

Originally Posted by JeffreyAK

Us physicists l... and the required decrease in mass per unit length required to explain that frequency change (twice that, if I did the math right).

Conclusion: A string can indeed stretch and deform a bit, but what I measured can't possibly account for the full half-step drop in tuning I heard. In fact it's nowhere close.

So what is changing? It seems unlikely to be the tuning peg, since the string was wrapped nicely and tightly. My guess, it's at the ball end somewhere, but that's a guess....

The mass-per-unit-length of the string has nothing at all to do with it's frequency. Your confusing point-mass (like a pendulum) where the natural frequency is affected by mass. The frequency is only (essentially) affected by the tension.

The wrapping of the strings on the peg is a whole science and likely where most of the slack always occurs.

[robj144]

Originally Posted by fazool

The mass-per-unit-length of the string has nothing at all to do with it's frequency. Your confusing point-mass (like a pendulum) where the natural frequency is affected by mass. The frequency is only (essentially) affected by the tension.

The wrapping of the strings on the peg is a whole science and likely where most of the slack always occurs.

The frequency depends on the mass/length, tension, and its length. The speed of the wave is the square root of the ratio of the tension and mass/length.

[fazool]

Originally Posted by robj144

The frequency depends on the mass/length, tension, and its length. The speed of the wave is the square root of the ratio of the tension and mass/length.

Ahh yes - thanks. I saw "mass" and jumped to thinking he was after pendulum style mass.

[JeffreyAK]

Originally Posted by robj144

The frequency depends on the mass/length, tension, and its length. The speed of the wave is the square root of the ratio of the tension and mass/length.

Correct. I don't know why fazool doesn't understand this.

[fazool]

Originally Posted by JeffreyAK

Correct. I don't know why fazool doesn't understand this.

I understand it - I misunderstood what you were saying - I thought you were talking about masses.

[JeffreyAK]

Originally Posted by fazool

The wrapping of the strings on the peg is a whole science and likely where most of the slack always occurs.

Possibly, but then one still has to explain the observation - made countless times by me in the past, and repeated last night - that once you "break in" a new string, you do not need to do it again if you take the string off and then put it back on.

Whatever is happening during break-in, appears to be happening to the string itself. A couple other things that are happening during this break-in are, the end of the string is developing a permanent helical coil from the peg, and the end by the ball is developing permanent kinks where the string goes out the bridge and again where it goes over the saddle. The tuning drop during break-in could be partly related to these permanent changes as well.

[fazool]

Originally Posted by JeffreyAK

Possibly, but then one still has to explain the observation - made countless times by me in the past, and repeated last night - that once you "break in" a new string, you do not need to do it again if you take the string off and then put it back on.

Whatever is happening during break-in, appears to be happening to the string itself. A couple other things that are happening during this break-in are, the end of the string is developing a permanent helical coil from the peg, and the end by the ball is developing permanent kinks where the string goes out the bridge and again where it goes over the saddle. The tuning drop during break-in could be partly related to these permanent changes as well.

That's so weird though because if you put a piece of guitar string on a tensile tester, it won't stretch, then stop. Intuitively, I think its going to neck down and snap with very little transition period.

You certainly bring up a compelling thought with your observations.

Maybe it's a combination of the two. Your initial deformation happens once, then any instability after that is slack. Perhaps.

[robj144]

Originally Posted by fazool

Ahh yes - thanks. I saw "mass" and jumped to thinking he was after pendulum style mass.

Actually a simple pendulum doesn't depend on mass either.