Understanding Putters: “Soft Feel”

December 17, 2012

If I’ve heard it once, I’ve heard it 1,000 times. Someone, trying to give a glowing review of a new flatsick to make others understand the new piece of equipment in its fullest, praises about how the putter has exceptionally “soft feel” at impact.

Ever wonder how a piece of steel could feel “soft?” I do.

Even though I know that steel is not truly soft–at least, not as compared to pretty much anything on this earth–I myself have used this phrase, as it’s understood in the vernacular of the golf industry to mean “that felt really good.”

The fact of the matter is that the hardness of the metal is fairly immaterial to whether a putter feels “soft.” There is one caveat–if the material is so soft that you can tell by feeling it with your finger that it’s soft, then it probably can affect the way the putter feels. However, that is not the case always, which leads me to the question–if someone could choose between a noticeably soft material and steel, why would anyone choose steel if the goal is “soft feel?”

The answer is that what “soft feel” really means is “how does this thing vibrate?” It is far more than just what your hands feel. It’s about resonance frequencies, amplitudes, and so much more.

The most often repeated myth about feel is that the hardness of the metal determines what is felt. I’ll explain shortly why that is incorrect. But a close second is the myth that “feel is ONLY sound.” I’ve heard this often from the great Scotty Cameron, and others, who claim that of you put headphones on and putted, then you would not be able to tell the difference between putters. This is inaccurate.

While sound does play a large role in the process, it is only because the sound is at the same frequency (or, in other words, same type of vibrations) as what you feel in your hands. You see, putters–like any other object–have a resonance frequency at which they vibrate. It’s a naturally occurring phenomenon that all things, regardless of size, have a certain vibration that they like. Like striking a bell, a putter will “ring” at its resonance frequency by default. It’s pretty difficult to get a bell to ring at a pitch other than its resonance frequency…..same thing with putters. Like a holding a bell, what you hear in your ear will be vibration at the exact same rate as what you are holding in your hand. In other words, what you feel in your hands is the same as what you hear in your ears. It simply can’t occur any other way.

Now, some have said that the effect of what you feel in your hands is so little that the sound really is all that matters. To those folks, I challenge them to play baseball in the winter time with an aluminum bat and tell me there’s nothing to feel in your hands. What you perceive as tactile feedback is far more precise than what you hear. If you don’t believe that, run your hand over a bumpy surface and tell me what it feels like. Then, sing against it and tell me if you can pick up the bumps with your ears. There is a great deal to be felt with your hands.

If that’s true, then what exactly is it that “feels soft” when it comes to a putter–or any club–striking a golf ball?

The answer is that there are two ways to create “soft feel.” The perception that something is “soft” is based on the idea that impact to soft things is typically low energy. Low energy is typically associate with lower frequency vibrations or very low amplitude–or, in other words, quiet. High energy impacts are loud (high amplitude) and high-pitched (high frequency).

Low energy impact feels like you’re making contact with a pillow. It feels like what you’re hitting is “soft.” High energy impact feels like you’re making contact with a brick. So the way to make a putter feel “soft” is to have a low frequency (i.e., low pitch) or low amplitude (i.e., quiet) impact.

To achieve the low frequency impact, it is important to make a putter that has a particularly low resonance frequency (the resonance frequency being the “ringing” frequency, at which a putter rings like a bell, as discussed earlier). Typically, a dense material will have a low resonant frequency by its nature. However, when a putter is designed to incorporate other factors–like, for example, making a 350-gram head–the design of the putter itself may become a factor in how much the putter vibrates. For example, copper putters often feel ringy and loud because they typically are made with thinner faces. Copper is a dense material as compared to steel, so it is difficult to achieve a comparably-weighted putter head with a similar design to a steel head, which is what most golfers are familiar with. As such, putters made of copper often have thin faces or extra ground soles to try and remove weight where the player will not visually notice it. However, both of these design elements result in a higher resonance frequency. Even though most bells are made of brass, which is a very dense material, small, thin walled bells can resonate at high pitches while large, thicker-walled bells resonate at lower pitches. As such, the design has a lot to do with how a solid (i.e., no insert) putter resonates and with what the player feels.

So, designing a putter to have low frequency resonance is one element that allows a putter to “feel soft.” However, the other option is just to make a putter that doesn’t really vibrate that much. This results in a different feel, but not a materially different one. Because the low resonance frequencies are typically low energy, they don’t typically feel very different from a putter that has a high resonance with very low energy or just no resonance at all. As such, one way to get a putter not to resonate at all is to put a soft insert material in it, such as plastic (Odyssey) or something even softer, such as STX putters, which were made with a deformably soft material. No one thinks of plastic as being soft or associated with low resonance. If anything, plastics have very high resonance frequencies, as they are very low density (light weight) and hard as compared to their weight. However, they can be engineered so as not to transmit vibrations very easily. That means that, even if the insert material has a high pitched resonance, it never gets transmitted to the user because it is almost no energy.

The same thing works with grooved or deep milled putters. The reason they feel “so soft” is that they do not transmit a much energy, as the impact with the ball must travel through the relatively small contacts with the ball to be transmitted up to the user and ring the putter head. Even some of the old putters–like the Scotty Cameron TeI3 series–felt soft only because they had a layer of “elastomer” (rubber) between the insert and the rest of the putter head that dampened the vibrations.

But why do golfers want something that feels “soft?” There are many explanations, and none of them definitive. One is that a well-struck ball will always have a relatively low resonance frequency because–if the club is designed correctly–that is the point of most efficient energy transfer. When you hit the sweet spot, it feels good; when you don’t, it feels bad. That’s because hitting the sweet spot doesn’t waste energy on twisting the club head, making an odd sound, and vibrating–at least, if the club is designed correctly. Another explanation is that golf has changed over the years. In the “old days,” golf balls were made differently. The old balata covers were much softer as enjoyable to putt with as compared to today’s so-called “soft cover” balls that would only pass as an intermediate ball back in the days of yore. Although the performance and durability of modern golf balls make it worth the changeover, players seeking that “old time feel” must change the putter, not the ball, to achieve what they’re “used to.”

What you like is up to you. Most players will like a low-pitched and/or low energy impact, but some don’t. I personally have a slot cut in my putter that intentionally reduces the thickness of the face, making the putter resonate a little more, and giving me a little more feedback on how I struck the ball. I don’t want it to feel ringy, but I do want to be able to feel the impact, so I’ve selected a putter that I believe meets my personal preference for feel. Many Tour pros play Odyssey putters, even though golf purists tend to scoff at insert-based putters. Many purists say that insert putters are not responsive. There is some truth to this, as inserts are there to dampen vibrations, not to give feedback. However, if it’s good enough for Tour pros, I’m not sure what everyone is complaining about.

In the end, every putter will have its own signature sound and feel because very few are designed exactly alike, and even those that are designed alike are typically made of slightly different materials or with slightly different processes. However, knowing and understanding the differences will help you find what it is you like and what helps you feel the best about your putting, which is the key to gaining confidence on the course.

One Response to “Understanding Putters: “Soft Feel””

  1. LimpingBassoon Says:

    Excellent explanation, thanks

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