Low Action on Bar Chord Forces

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cathulu

Posts: 950
Joined: Dec. 15 2006
From: Vancouver, Canukistan

Low Action on Bar Chord Forces

I am sick in bed, so I figured I would see what the bar chord forces on the index finger were depending on the action of the guitar. This is for the index finger barring across all six strings, assuming hard tension.

I assume that the tension in the string basically does not change in my simple calculation, safe to assume for low string displacements.

The upshot is that if your set-up is 50% higher than a good set-up then the force will be 50% more. Kind of obvious, yes I know. But the magnitudes range from about .5 kg force for 2mm displacement to about 1.5kg for 6mm with hard tension strings.

This can really tax your hand if your guitar is not set-up well. Those of us working with beginner guitars or guitars not set-up usually have high action, we are struggling more than we should. No one ever told me this!

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REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 14:43:42

Munin

Posts: 595
Joined: Sep. 30 2008
From: Hong Kong

RE: Low Action on Bar Chord Forces (in reply to cathulu)

It's really true - when I still had my old crummy classical guitar, barre chords were doable, but I always assumed that my relative trouble with them (especially for longer durations, more complex additional fingering, etc) was due to my limited playing ability more than the actual guitar. I was pretty surprised when I held the guitar of my teacher in my hands for the first time. It was a complete breeze.

This is one of the reasons why I feel it's - at least partially - wrong to make a blanket statement such as "a better guitar does not make a better player". On a fundamental level, that is of course true, but all those little things can add up to a lot in the end, ESPECIALLY if you're still a beginner.

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 14:52:04

gj Michelob

Posts: 1531
Joined: Nov. 7 2008
From: New York City/San Francisco

RE: Low Action on Bar Chord Forces (in reply to cathulu)

Cathulu... you are measuring the strings height/distance at the 12th fret, correct?

Also, why would you assume hard-tension strings to be the norm (i do not mean it, as it could sound, as a confrontation on tension, just always curious)?

Munin, perhaps your absolutely valid statement could be tone down a notch, not so much that a better guitar makes a better player, but certainly one that is set up well !!

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gj Michelob

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 15:11:24

cathulu

Posts: 950
Joined: Dec. 15 2006
From: Vancouver, Canukistan

RE: Low Action on Bar Chord Forces (in reply to gj Michelob)

I assumed the tension was applied mid-string. But I don't think there is a big difference where the tension is applied unless you are real close to the nut, like the F Chord, where I think it may be higher because the geometry of the string and the force diagram. The G chord at the third fret is probably the easiest to finger with everything getting harder whichever way you go.

FYI, my guitar is 5mm from the center of the low e-string to the fret board at the 12th fret. I believe it is supposed to be around 2.5 to 3 mm?

I just used hard tension cause that is what I could find easy on the net for string tension. I actually use medium D'Addario myself. I understand there is not a huge difference in tension, less than a kg between them per spring.

PS if I include F=kx, i.e. that the string stretches when you displace it like a spring, then the finger forces will grow with the square of the string displacement. So you will be working a lot harder! I do wonder when this effect kicks in, not over a couple of mm but maybe when you get around 5mm or more the spring effect will start to be noticeable.

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 15:47:12

gj Michelob

Posts: 1531
Joined: Nov. 7 2008
From: New York City/San Francisco

RE: Low Action on Bar Chord Forces (in reply to cathulu)

quote:

(Cathulu) FYI, my guitar is 5mm from the center of the low e-string to the fret board at the 12th fret. I believe it is supposed to be around 2.5 to 3 mm?

wow all my guitars are set at 2mm, with frets as low as they can (another interestingly often underestimated or overlooked part of the problem)... nrmal tension... easy life...

You are certainly correct about the small variation caused by medium or hard tension compared to normal. However, little things such as that will become more meaningful over time, within a palying-session or in the long run.
At least, my palying improved drastically when i finally listened and switched to normal tension. However, i maybe a fragile man, after all... with plenty of room to improve.

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gj Michelob

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 16:24:44

cathulu

Posts: 950
Joined: Dec. 15 2006
From: Vancouver, Canukistan

RE: Low Action on Bar Chord Forces (in reply to gj Michelob)

Hey, thanks for that. I will take fret height into consideration with my next guitar. Never would have considered that.

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 16:37:04

gj Michelob

Posts: 1531
Joined: Nov. 7 2008
From: New York City/San Francisco

RE: Low Action on Bar Chord Forces (in reply to cathulu)

quote:

Hey, thanks for that. I will take fret height into consideration with my next guitar. Never would have considered that.

I had Richard Collopy here in SF take accurate measurements of my holy grail, the Conde AF/25 R. Action is set a 2mm over the 12th, and frets were twice as lower as any other of my guitars, save for the Francisco Navarro student model measuring the height of the frets simlarly to the Conde. I do not have the numbers, but i will gladly post them tomorrow, just for reference. Of course lowering the frets is not as easily reversed as lowering saddle or nut, caution should be in order.

Another problem which my result in fatigued hands is the strings alignment, which seems quite subjective a choice amongst makers. I suppose if nothing else one should make sure a new guitar has the same strings alignment one is used to in order to avoid awkward movements thorugh apparently imperceptible distances.

Incidentally, i have been complainig for ten days about an aching index finger that's unjustly and painfully deprived me of playing. The same luthier suggested that i soak my hand in Hot Water -after using ice to reduce the swelling. I did and healing is miraculous: as they say.... I discovered Hot Water !!

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gj Michelob

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 5 2009 17:57:38