String fretting force measured

[Gress]

I love the tone of Martin 12.5-55 strings. They are a perfect match for my Martin GPC-16e.


They are easy to play too. Out of curiosity I decided to measure albeit not very scientifically, the minimal pressure it takes to fret a clean note string by string. I may compare it to 12-54 next time I change the strings. For now here goes.

I took a 50 N ( or 11.24 pounds full scale) force gauge and a little cup I put on the probe which is very close in the tip size to a fingertip.


Here it is set to Lb and zeroed in


I decided to measure the pressure at the 3rd fret i.e 1/8 of the full string length and a bit away from the nut, so it's less contributing to the results.




Results (in pounds):
E- 0.52
A- 0.50
D- 0.55
G- 0.49
B- 0.44
E- 0.41

These are done by pressing on each string for a clean note and then decreasing the pressure capturing the min pressure before buzzing starts.

All done manually, so take it for what it worth ×/-

[The Bard Rocks]

Interesting. Especially so since the effort to make a string sound clearly is part of what makes a guitar easy or hard to play. I have not heard of anyone else doing that and it is probably worthy of far greater experimentation..

[birdsong]

Nice. This is very interesting. And as the Bard indicates, this would be an interesting exercise to do on a variety of instruments.

[abn556]

This is very interesting. I wonder about trying it on guitars that feel harder to fret to your touch and what the results would show. Like an acoustic with high, stiff action vs a electric with low, slinky action.

[Gress]

Thank you for your interest. I found this to be interesting question too and this is why I decided to measure it.
I am not sure what are the values measured by others, if any.

What started it for me was using "in the middle" Martin 12.5-55 strings. The strings, compared to 12-54 sound better with just a small change in the comfort of playing.

I am interested to learn what are usual values and statistical distribution that are known. Failed to find any info on that.

Originally Posted by abn556

This is very interesting. I wonder about trying it on guitars that feel harder to fret to your touch and what the results would show. Like an acoustic with high, stiff action vs a electric with low, slinky action.

For WIW I did it on my Martin GPC16e. The setup is lower than Martin specs and is at 2.25 mm height for E and 1.75 for e string with the neck relief at nominal .008

I do not have a guitar with harder setup. My other 2 are similarly set and have lighter strings.

[sinistral]

I can see several applications for this type of measurement. For example, we all have one or more guitars that feel just right. It would be interesting to measure the minimum string tension to fret a clean note (“MSTFCN”) of the stings at various frets (e.g., 1, 3, 5, 12, etc.) and use it as a reference in addition to 12-fret action, etc. as part of the setup process for other guitars. It would also be interesting to measure the before and after results when setting up a guitar. For example, if a guitar has high nut slots and high action at the 12th fret, I would be curious what the MSTFCN is before and after each step in the setup process (i.e., lowering nut slots, shaving saddle, etc.). We all know intuitively that it takes more pressure to fret a clean note on a guitar with high action, but I’ve never heard of anyone quantifying just how much. As noted, it would be interesting to compare the MSTFCNs of one’s acoustic guitars and electric guitars. Very cool experiment.

Just one question though—does the meter prefer a 1-11/16” or a 1-3/4” nut?

[Alan Carruth]

Gress wrote
"I am interested to learn what are usual values and statistical distribution that are known. Failed to find any info on that."

So get the data!

Given the degree of uncertainty in a hand measurement, there are two ways you can go. One is to make a lot more measurements in the same way, and run the analysis. The other is to devise some sort of setup where the gauge is held in a fixture that allows it to be moved in a more controlled manner. Either way you'll get some variation in the results, but with better control there should be less variation, and you can rely on a smaller sample.

I'd love to see this applied to instruments that 'feel' different, despite having similar setups. It could go some way into settling the discussion of why that happens.

Forty or fifty years ago it was really hard to get good data on a lot of aspects of the way guitars work, and as a result there was a lot of uninformed speculation, some of which hardened into myth. We still deal with that now, but it's gotten a lot easier to at least make the measurements that could answer those questions. Myths, of course, persist, even in the face of facts, but at least we can arm up for the conflict with good data.

[DDW]

I too am quite interested in this. Real data is somewhat rare in the guitar and music world.

Do you have a link to where you purchased the device?

[Gress]

Originally Posted by DDW

I too am quite interested in this. Real data is somewhat rare in the guitar and music world.

Do you have a link to where you purchased the device?

Here goes
https://www.amazon.com/Mxmoonfree-Di...51&sr=1-1&th=1

[Gress]

Originally Posted by sinistral

I can see several applications for this type of measurement. For example, we all have one or more guitars that feel just right. It would be interesting to measure the minimum string tension to fret a clean note (“MSTFCN”) of the stings at various frets (e.g., 1, 3, 5, 12, etc.) and use it as a reference in addition to 12-fret action, etc. as part of the setup process for other guitars. It would also be interesting to measure the before and after results when setting up a guitar. For example, if a guitar has high nut slots and high action at the 12th fret, I would be curious what the MSTFCN is before and after each step in the setup process (i.e., lowering nut slots, shaving saddle, etc.). We all know intuitively that it takes more pressure to fret a clean note on a guitar with high action, but I’ve never heard of anyone quantifying just how much. As noted, it would be interesting to compare the MSTFCNs of one’s acoustic guitars and electric guitars. Very cool experiment.

Just one question though—does the meter prefer a 1-11/16” or a 1-3/4” nut?

Coming from physics and math, I think the suggested name should be "minimum string FORCE to fret a clean note (“MSFFCN”)". Tension of the string is something different.
And I noticed that I myself did it wrong using the word pressure in the title. It is actually the force what I had measured and I did not calculate it to pressure. So I corrected the title

I am with you on your suggestion. It would be very interesting to see the data like you suggested.

And, yes, the meter prefers wider nuts, as the cup on the probe is more comfortable going on one string only and not touching the neighboring ones with more distance string to string.
To be accurate, this is the cup preference, not the meter...

[Gress]

Originally Posted by Alan Carruth

Gress wrote
"I am interested to learn what are usual values and statistical distribution that are known. Failed to find any info on that."

So get the data!

Given the degree of uncertainty in a hand measurement, there are two ways you can go. One is to make a lot more measurements in the same way, and run the analysis. The other is to devise some sort of setup where the gauge is held in a fixture that allows it to be moved in a more controlled manner. Either way you'll get some variation in the results, but with better control there should be less variation, and you can rely on a smaller sample.

I'd love to see this applied to instruments that 'feel' different, despite having similar setups. It could go some way into settling the discussion of why that happens.

Forty or fifty years ago it was really hard to get good data on a lot of aspects of the way guitars work, and as a result there was a lot of uninformed speculation, some of which hardened into myth. We still deal with that now, but it's gotten a lot easier to at least make the measurements that could answer those questions. Myths, of course, persist, even in the face of facts, but at least we can arm up for the conflict with good data.

Coming from science and working in the HiTech for decades, the pure statistical approach could be much improved by employing physical models.

So while looking for the formulas I found a page for electric guitar theory.
From there the formula for the fretting force is:

F=(T+EA(1-cos(Alpha))/cos(Alpha))sin(Alpha)

where:
F is fretting force,
T is string tension
E is Young's modulus
A is cross sectional area of the string
alpha is the angle the depressed (fretted) string makes with horizontal line

knowing the parameters and esp the Young's modulus, as the rest is easy to figure out the force could be calculated.

As always, the model is just an approximation and would not be exact. So based on the force measurement like the one I did the model outcome could be compared to real force as measured and a correcting coefficient could be calculated and applied.

Once these is done, the formula could become a good way to calculate the force for different strings (i.e. different T, E and A) and at different frets - different Alphas.

Perhaps one day I open a reference book for the material properties and fill in the missing parameters.

Or someone else who is interested can take over

[Gress]

For now I just did a barre force measurement at the same 3rd fret. I should say that positioning of the bar within the fret contributed a lot.

The reliable fretting required is around 5 lbs, which is way more than it should be based on individual string forces.

However after experimenting and trying to find the lowest force possible while moving within the fret and trying to hold the meter perpendicular to the pencil etc.the min force I registered was 2.96 lb

[DDW]

The barre measurement was done on a guitar with a radiused fingerboard? So the strings and frets define an arc? That might affect the measurement. On a classical guitar with a flat fingerboard, perhaps more accurate?

I am intrigued enough to order the meter.

[Gress]

Originally Posted by DDW

The barre measurement was done on a guitar with a radiused fingerboard? So the strings and frets define an arc? That might affect the measurement. On a classical guitar with a flat fingerboard, perhaps more accurate?

I am intrigued enough to order the meter.

Yes. I did my best profiling the pencil I used to match the fretboard, but this was not perfect, obviously.

[Sev112]

This is the best thread I’ve read in ages Bravo

Am so tempted to get one of those gauges