As the title implies, I am interested in learning more about the significance of the “tone” an individual blank emits when struck or tapped on its side or dropped on its butt. It is very intriguing to me after learning about it a few months ago here on this site; and it has been mentioned a few times since. Apparently it is nothing new = some responding veterans claim to have been using the process for years. Although today, with modern technologies, I suppose the “tone” or “frequency” could be precisely measured, for all intents and purposes the process has previously relied on a “tuned ear”. How can I “tune my ear”? More importantly, what exactly does a “tuned ear” hear when a blank is “rung”? In simpler terms, what does a specific tone represent in a blank?
The common denominator or reference suggests the emitted tone has more to do with “sensitivity” than anything else. Given the same material and manufacturing process employed, I would think a thicker-walled or larger diameter or longer blank would produce a lower tone than a thinner or smaller diameter or shorter blank. That would seem to imply that the latter is more sensitive. And then, would a lower modulus blank with thinner walls or smaller diameter or shorter length produce a similar tone compared to a higher modulus blank which is thicker walled or larger diameter or longer length?
Please help me “hear” the whole scenario; I am “hear” to learn (sorry, I couldn’t resist).

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Here is a nice $10,000 machine to measure harmonic frequencies.

[www.ndtjames.com]

Touche Roger. Great reply and link. Now all we need is someone to step-up-to-the-plate and purchase one. With the hordes of money involved in custom rod building, there may be numerous takers lol.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Actually, I was hoping for a more “seat of-the-pants” explanation.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Let's look at some examples. A tuning fork gets it's harmonic frequency by the material used, the hardness of that material, and its length. All things being equal, shortening the tuning fork doesn't change the tone, so much as dampen it. However, lengthening it produces the same tone, but requires more energy input to do so. Now, let's examine string instruments. The thicker, longer strings produce lower frequencies than the more slender shorter strings. The frequency of the strings is also determined bt the amount of stress placed on the strings. Te more stress, the higher the pitch. All that being said, the stiffness of the rod, coupled with its length will determine how well the rod blank transmits vibration to your hand. A higher modulus rod transmits better than a lower modulus rod, as it is less prone to absorbing harmonics (vibratios). The problem is that higher modulus rods are more brittle, so a ballance must be maintained to allow the rod blank to withstand the forces applied to it. For me, looking at the blank construction is more important than blank frequency. Thin walls, with micro fibers running in a paralell line from but to ti will give you max sensitivity, and tensile strength, A spiral wound core gives hoop strength, keeping the hoop from collapsing. Some rod manufacturers use carbon fiber, with a small amount of boron, graphene, kevlar, or other additives to make their rod blanks stringer, while others claim that this is a gimmick, and that proper construction is all important.

As long as the rod blank is within my budget, and does the job it's supposed to do, well that's what all this is about. Just like many lures, I believe many fishing rods are made for catching fishermen, and fisher-women. I mean. do you really need a jewelry quality agate stripping guide to catch fish? I've caught more fish on a child's fiberglass rod, with a Zebco 202 reel than I have with my Winston BIIIX, though that rod is still a wonderous thing.

Seeeeya; Chief Longwind of the North

Tight Lies and frisky fish

RJF

I would purchase one of Roger's machines, but I don't have many 6 inch blanks. :-)



Edited 1 time(s). Last edit at 03/27/2022 08:51AM by Michael Danek.

Robert Flowers Wrote:
-------------------------------------------------------
> do you really need a jewelry quality agate stripping
> guide to catch fish?


Robert I will answer your question with one word and then the villagers will be after me with pitch forks and torches.

Here goes..... "EGO"

Here they come, bye

Have fun

John

Harmonic frequencies are expressed in numbers; vibrations per second I believe? What would be a "good" frequency for a rod to have, and what would be a "poor" frequency for a rod to have?



Edited 1 time(s). Last edit at 03/27/2022 09:56AM by Phil Ewanicki.

Hi Mark,
I am trying to help answer your questions from my experience (vibration analysis of fans, blowers, motors in an automotive factory). If a rod blank were a machine it could be analyzed many ways. A person could walk into the room and say the machine sounds good/ or not. A person could put a screwdriver from their ear to a bearing housing and listen to the bearing, race, etc., and say it was good/ or not. A person could put a probe on the bearing housing collect data and then trend the data and possibly predict when the parts of the machinery would fail.
I think the screwdriver approach would be closest to the "tuned ear". Listening to the same type of rod blank enough times could bring good results.
There are some other things to consider. For me, the harmonics (1x, diminishing to 2x, 3x...), are always in terms of running speed (RS)of a machine. the main exciter being 1x times RS. So if you change the running speed, the harmonics will differ. So if you rely on a tuned ear it might say one thing for a 6' blank tapped on a tile floor, and something different for a different surface.
Resonant frequency was something that we had to keep away from the running speed of the machine because of all the increased vibration. We could change the resonant frequency by stiffening (higher modulus?) or adding weight (heavier blank, guides, components?) to the frame of the machine. The machine frame could be lightened (higher modulus?) or weakened (lower modulus?) to also reduce vibration at the running speed. I am thinking that as long as the tap (running speed in a machine) is the same, that a lot of variables could sound similar to a "tuned ear". I think that it would be good to train the ear on similar lengths, weights of blanks.
Hope this is more clarity than mud!

Mark as you know : Michael Danek has suggested an affordable method to measure TNF. I had suggested an accelerometer in the past and they are now affordable. I had also suggested looking at studies done on materials for long canes The rod is a finished product so the handle material and shape should not be ignored.

The degree to how any measured parameter translates to a finished product is very much open for debate. Trial and error among rod builders has lead many of us to the conclusion that a higher TNF does equate to higher sensitivity. It has also been noted that blanks that have that brittle glass ring when the butt is dropped on a hard surface seem to be the ones with higher TNF.

One would think we should concentrate our measuring at the butt end. The range of hertz you are going to see for a blanks TNF is one thing. But what can our hand detect and what area of it is most and least sensitive? What role does the shape and size of the handle play in this? Again we must look outside the area of fishing rods for published studies.

Good luck with this.

Russ in Hollywood, FL.

Thank you for the replies from Robert, John, Gary, Russell, and even Roger and Michael lol. The replies certainly added some fuel for thought. I am still trying to wrap my head around Robert’s comment “All things being equal, shortening the tuning fork doesn't change the tone, so much as dampen it”. I would think changing the length of the tines of a tuning would CERTAINLY change the tone. Gary offered good analogies between blanks and his previous vibration analysis experience. Russell took it a step further and questioned how “sensitive” a blank might be at different points along its length and how much grips “deaden” the sensitivity.
While all are appreciated and informative replies, I have not received any replies from the “Tap Master” veterans explaining how they perform their “rod ringing” procedure, what they hear, and what it means. I am very intrigued and interested to learn.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

And all of this will help you catch more fish? Haha! SMH!

Let's see if I can use the harmonics data? To my customer: this blank has way better harmonics then the one you were thinking about, his response......so what!



Edited 1 time(s). Last edit at 03/28/2022 12:07PM by Phil Erickson.

Tim,
Isn’t that a custom rod builder’s ultimate goal; to build a rod which catches more fish than other offerings? While there are certainly a host of other uncontrollable variables, ringing a blank may be one of them, the well-versed rod builder most likely has an edge over others who simply thread wrap guides onto a stick. I can’t imagine obtaining as much information as possibly being a bad thing. Although this “rod ringing” could be considered Voodoo by some, I find the possibilities intriguing and simply want to learn more. Afterall, we are all here to learn….hopefully. By the way, excuse my ignorance, but I do not understand “SMH”.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Shaking my head!

Tim,
Thanks for the “SMH” explanation. You may not be the only veteran shaking their head at the rod ringing method; to be honest, my novice head is shaking a bit as well but I would still like to learn more before discounting, disregarding and discarding it; I haven’t been-there-done-that yet. There is some intriguing merit there that I would like to explore if I could only get some “rod ringers” to help me get to that point. The funny thing is that there were a number of “rod ringers” contributing before; where are they when I need them? Otherwise, I may be forced to join you in shaking my head and consider “rod ringing” simply a meadow muffin story; I hope not!

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

It amazes me how incurious some people are. And how many responses there are on forums regarding rod sensitivity, with builders purporting to know exactly the relative sensitivity of different blanks, extolling their favorites, and they have absolutely no objective data to support their claims. Then when someone tries to investigate the subject to improve our knowledge, they "DISS" the attempt.

So let me asked a question here. You are going to build a rod. You order the blank with all the specifications that you want and the price range you want. You’re happy when you get the blank and can start the rod build. Now you do whatever it is to “ ring the rod blank” and you don’t like the ring tone, what do you do now? Send the blank back and tell them it doesn’t ring right, put it in the corner or throw it away. Just curious!

When it comes to the relationship between the normal modes (fundamental and harmonics in transverse and longitudinal waves) of a rod blank and sensitivity, higher is better.

Transverse waves are waves where the displacement of the blank is perpendicular to the direction of propagation, i.e. the movement used when measuring CCF or Mick's technique for measuring the natural frequency of a blank.

Longitudinal waves are waves where the displacement is along the direction of propagation. These are the 'ringing' waves described by Kent and referenced in this thread.

The reason that higher frequencies are better is because they are associated with a higher wave velocity. Wave velocity can be calculated two ways, one by using the properties of the wave v = frequency times wavelength. Since the length of a blank is fixed, the wavelength of the fundamental and its harmonics will be fixed based on the geometry of the blank. So, all else being equal, the blank with the higher frequency will have the higher wave velocity. The other way to calculate wave velocity is based on the properties of the medium itself. The equation takes the form v = square root(Tensile Property / Inertial Property). I do not know the exact forms of these equations for a tubular beam with variable cross-section and variable thickness. For the transverse waves the modulus of elasticity is very likely to appear in the top of the fraction and the moment of inertia is very likely to appear in the bottom of the fraction. The longitudinal equation will have similar form, but different parameters for the numerator and denominator. This means that comparing blanks with very similar length, action, and power, the one with the highest modulus will have the higher wave velocity and therefore highest frequency. Additionally, the rod with the lowest inertia (lowest mass, and density) will have the highest speed and therefore highest wave velocity and frequency as well.

When it comes to training your ear, I don't think you need to do much beyond recognizing a higher pitch vs a lower pitch. The best blanks defined by dropping the blank butt on a hard surface will be the ones with the highest frequencies.

Mark, your instincts about length and wall thickness are spot on.

Mark, you also hit on one of the challenges with this type of analysis, and that is that the resonant frequency depends on a number of factors. You may find a shorter large diameter thin walled blank of lower modulus that matches the resonant frequency of a longer thick walled high modulus blank. That is the nature of the physics. The natural frequency of a blank is a differentiating parameter of blanks with very similar length, action, and power. If you have a preferred blank that is no longer in production, you can replicate it pretty much exactly if you can match the length, action, power, and frequency.

Something that may be of additional interest to some of the curious minds here is a white paper that found its way into my inbox recently via Physics Today.

[engage.physicstoday.org]

The paper is primarily for marketing, but it talks about resins that cure via UV exposure and Heat. I seem to recall someone implying in the past that some blanks may have gotten better over time. This may be due to additional hardening of the thermoplastic resin after extended exposure to UV light in the fishing environment. It certainly offers up another nuanced thing to think about, as I would not be surprised to see composite manufacturers moving to these types of hybrid curing resins to reduce cure time and increase production volume.

Tim, I do not build in high enough volume to be able to fuss over the longitudinal frequency (ringing frequency) of a blank, although I certainly understand why it's a good thing. However, when given the opportunity to handle a bunch of blanks in person, a combination of basic visual inspection, flexing, and ringing the blanks can allow for the opportunity to select the best available. Without access to a large blank inventory, you get what you get, unless you are willing to set the blank aside and order another.