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Ukulele Strings in the Past, Present and Future: Chapter 3

1 Introduction

More in the series, "Ukulele Strings in the Past, Present and Future", now with Chapter 3.
Previously I have offered "The Gut Strings of 40 Years or More Ago" in Chapter 1, and "The Newest Gut Strings" in Chapter 2.Now I introduce "The Gut String of the Future" in Chapter 3.

If it is a gut string, it will be known to Mr. Masami Matt Kobayashi of the Nihon Ukulele Association (NUA).
And although he didn't mention where he got them from, a surprising gift of strings arrived from him.
The name of the strings is NYLGUT. And what kind of string is it?
Well, let's investigate the nature of the NYLGUT strings.

2 NYLGUT Strings

They are strings made by Aquila of Italy introduced in Chapter 2.
When I took a Nylgut string out from the bag, it appeared more like a thin flexible white stick of plastic rather than a string. It has some texture in it's feel to the touch.

According to Matt, the string called NYLGUT is a patented product, "the first synthetic gut in the world" with the character similar to gut strings, and tone quality resembling gut very closely, but lacking the pitch change to the temperature which a gut has. The fault "be easy to cut" were compensated by this.

If the patent information is obtained, although the quality of the material etc. should be known, the quality of the material and the process are "being a secret entirely."

The material of a Nylon family was presumed since the word NYLGUT starts with Nyl-. But according to the sales representative, it is a material with density higher than Nylon, (for this reason, it sustains the same pitch with a gauge thinner than nylon), and it is similar to the material currently used for the dashboard of a motor vehicle.

As a result of finding in the technical books of a plastic, Matt concluded that the material is possibly POM: Polyoxymethylene (widely known as Polyacetal), a completely different plastic from Nylon. Since the density of Polyacetal is 1.41, a little more than 20% heavier than Nylon, which has a density of 1.14, and the material color is white and is used for the interior of a car, it is presumed to be true.

Supposing it is Polyacetal, it has the outstanding characters such as 1/3 to 1/4 of length deviation by adding tension from Nylon, and also 1/6 of hygroscopic character from Nylon.

Since its density is higher than Nylon and almost the same as a gut, the gauges of 1st string:0.56mm, 2nd string:0.73mm, 3rd string:0.91mm, and 4th string:0.62mm were chosen by Matt.

And although it was first thought that the gut strings of Aquila had the same density as Nylon and 1st string:0.64mm, 2nd string:0.82mm, 3rd string:0.91mm, and 4th string:0.70mm were chosen, and characteristics measured in Chapter 2, the tension was too high. I tested the 0.56mm, 0.73mm, and 0.62mm the same gauge of NYLGUT strings sent from Matt this time. This is almost the same combination as the gut strings of the ukulele set of SAVAREZ in Chapter 2.

Following are the gauges for each string set I tested.

Classification 1st string 2nd string 3rd string 4th string


NYLGUT 0.56mm 0.73mm 0.91mm


Aquila Gut (1)
(normal tension)
0.56mm 0.73mm 0.91mm 0.62mm 3rd is roped string
Aquila Gut (2)
(high tension)
0.64mm 0.82mm 0.91mm 0.70mm 3rd is roped string
Saverez Gut 0.58mm 0.74mm 1.10mm 0.63mm 3rd is copper wound
ghs (reference) 0.63mm 0.81mm 0.91mm 0.71mm Nylon string

Aquila Gut (1) is the set of the same gauge as NYLGUT string and Aquila Gut (2) is the set of the almost same gauge as a ghs string.

Then, please listen sound first.

NYLGUT (My Dog Has Fleas) (39KB),Aquila gut (1) (My Dog Has Fleas) (46KB)

How is it? Is the distinction hardly noticeable?
Then, let's investigate in detail and go.

3 Analysis

(1) Waveform Analysis

The waveform of each string was investigated based on the data of (My Dog Has Fleas).

  1. NYLGUT strings
  2. Aquila Gut (1) normal tension (the same gauge as NYLGUT)
  3. Aquila Gut (2) high tension (almost the same gauge as ghs)
  4. ghs (Nylon strings)

Then, please have a look from 4th string

4th String (G)

Envelope of Waveform

Sounding Duration Time



Aquila Gut (1)


Aquila Gut (2)




As for the upper three pictures, sound is once decreased after the attack of sound.
The duration of sound of Aquila Gut (1) is longer, although Aquila Gut (1) and Aquila Gut (2) have an almost the same waveform, since only the tension is different with the same gut.

Next is 3rd string.

3rd String ( C) Envelope of Waveform Sounding Duration Time



Aquila Gut (1)


Aquila Gut (2)




Two Aquila Guts are the same gauge. Because it is roped gut, the attack of sound is delayed.
The peak of attack is late a little from the ghs string, and it turns out that NYLGUT string is close to a gut string.

Next, this is 2nd string.

2nd String (E)

Envelope of Waveform

Sounding Duration Time



Aquila Gut (1)


Aquila Gut (2)




NYLGUT and the two Aquila Gut strings are very much alike. They decrease immediately after the attack, and after swelling once on the way, decrease again. The ghs string of Nylon smoothly decreases.

Finally, this is 1st String.

1st String (A)

Envelope of Waveform

Sounding Duration Time



Aquila Gut (1)


Aquila Gut (2)




The waveform envelopes of the NYLGUT string and Aquila Gut (2) string have a strong resemblance to each other, but because the tension of the NYLGUT string is lower, it shows longer duration.

(2) Frequency Analysis

Then, a frequency analysis of each string was performed.

@ 4th String (G) 3rd String ( C) 2nd String (E) 1st String (A)
Gut (1)
Gut (2)
I was surprised. The NYLGUT string and Aquila Gut (1) and Aquila Gut (2) strings show the almost same frequency characteristic.
  1. 4th Strings: For NYLGUT, Aquila Gut (1) and Aquila Gut (2), although second harmonics components are not conspicuous, third harmonics components have come out strongly, and higher harmonics components than 4th are gradually decreasing.
  2. 3rd Strings: Second harmonics components of NYLGUT, Aquila Gut (1) and Aquila Gut (2) are low, having come out as fundamental components, though the second harmonics component of ghs has same level of intensity of the fundamental component.
  3. 2nd Strings: NYLGUT, Aquila Gut (1) and Aquila Gut (2) have low levels of 4th harmonics components, and have high levels of 5th harmonics components.
  4. 1st Strings: Although NYLGUT, Aquila Gut (1), and Aquila Gut (2) have a peak in 5th harmonics components, a ghs string has a peak in 4th harmonics component.

I summarize this test as:

  1. Although the waveform of NYLGUT strings is similar to the gut strings, sound duration is longer than gut strings.
  2. The frequency characteristic of the NYLGUT string is almost the same as a gut string.

Therefore, the "First Synthetic Gut in the World" with characteristics similar to gut, the NYLGUT string sang, and it was proved that the claim is valid.

4 Conclusion

The characteristic of a NYLGUT string has been checked through this experiment.
It is the String of the Future, which inherits completely the sonic features that are excellent in the gut string.
In addition, the price of a NYLGUT string is almost a half of a gut string. Isn't it good for us?

Now, where can we get these strings?
It is introduced in detail with the" Do you want to change your strings and where can you buy them?" page in COBA STUDIO( Mr. Hiroshi Kobayashi).
By all means, please visit the page!

Finally, the past, the present, and the future of a ukulele string can be understood through the complete Chapters of "Ukulele Strings in the Past, Present and Future". I am thankful to Mr. Masami Matt Kobayashi from the bottom of my heart.

<This translasion is supported by Mr. Curtis Daily of Aquila USA.>

5 Appendix

If there is time, please listen to the performance by the NYLGUT strings.

Crazy G (252KB)

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