Like baseball pitchers, many (if not most) golfers use sound for feedback to evaluate shot quality. In 2005, J.R. Roberts and others at Loughborough University in England conducted a research study* using surveys and ratings to investigate how golfers reacted to the sound of clubs. The golfers in the study were a mix of mid-handicap club professionals and amateurs. On the impression conveyed by sound, Roberts stated, “Sound also appears to have a psychological effect on the golfer; louder, crisper sounds, generated by modern, hollow metal club heads, give the golfer the impression that the ball has been propelled from the clubface faster and will, therefore, travel further.” We must add, though, there are times when sounds do not produce the experience above, perhaps making some, professionals and amateurs alike, biased about club choice. This is precisely why we want to look at how the sound/emotion connection works for golfers.
A Quick Bit of History
For the record, the earliest metallic ringing golf product was the Ping 1-A Manganese Bronze putter, introduced in 1959. The sound was so notable it became the name of the respected Ping brand.
Modern equipment manufacturers moved away from persimmon and cherry (hardwoods) to multi-part steel drivers in the late 1970’s. Today’s drivers are made with titanium with composite materials. Along with larger club head volume and a metal face came extraordinary sounds. Of note were Callaway’s Big Bertha Hawkeye and Warbird drivers in the nineties, which produced rather significant sound pressure levels (e.g., they were loud). Now, it is standard to hear the sound of metal emanating from every tee box on every course.
Metal Clubs: A Sound Science
Manufacturers take the science of golf club sound seriously, as sound is an integral part of the golfing experience. Sound for golfers equates to comfort, build quality, and therefore brand identity and loyalty. The importance of consumer perception has been a key part of some of Acentech’s “sound quality” work on various products, including golf clubs. David Bowen, the Director of our Noise and Vibration Group was able to talk to me about his experiences:
“In one project with a major golf club manufacturer, I and others developed analytical and numerical models of the club head, its dynamics, and the force pulse between the ball and the club, to help determine how best to modify and ‘fine-tune’ the head and its inner mass/spring systems in order to optimize the sound heard when the club strikes the ball. This was the sort of project that got us to flex our muscles in computer modeling, estimation of vibration response and sound radiation, precision sound and vibration measurements, and designing for product sound quality (and a little bit of arm/shoulder muscle flexing thrown in as well!).”
Below are spectrogram images showing how the frequency content of the sound produced by a club head striking a ball changes over time. Figure 1 is a spectrogram of a conventional metal driver with some internal tuning. Notice how the frequency distribution and duration is less than uniform. Figure 2 is a spectrogram of a club that is tuned to produce more even and shorter duration tones at desirable frequencies. The more pronounced red and green streaks in the conventional driver spectrogram correspond to higher levels and longer lasting sounds at higher frequencies, while the sound of the tuned driver is more uniform. In layman’s terms, this means the sound of the second club makes a more distinctive, consumer-preferred “thwack” when making contact with the ball.
Figure 1 (left): Spectrogram of conventional metal club
Figure 2 (right): Spectrogram of a sound-optimized club
Note: audio frequency (Hz) is indicated along the vertical axis of the chart. Time, in seconds, is indicated on the horizontal axis.
On The Course
What does a better understanding of sound mean for golfers who want to learn and improve their game? PGA Pro Section Teacher of the Year Rebecca Dengler, of Ed Oliver Golf Club was asked to give us some insight on what the acoustics of golf does for players and golf students and how sound plays into motivation. Rebecca summarizes:
Some players are more aware of certain senses and for those that are high in their auditory senses, sound is a big motivator. While fitting, I have had players comment on being very aware of the sound that the club makes when it contacts the ball. If this is very motivating to them it could inspire them to buy or not buy a particular club. Again, if a player attaches to the sound and relates that to a good shot it can be a positive motivating tool. Players can become very aware of the sound and try to recreate that sound of good impact in their swing. Also depending on the sound some players are very aware where the ball made contact on the face by the sound and this can help them make positive adjustments in their set up or swing. Various teacher and coaching programs have used the various learning styles of auditory, visual or kinesthetic to help people learn more effectively.
Final Swing Thoughts
There are hundreds of golf club reviews on-line, and in many the reviewer’s last dialog is a description of how the club felt and sounded — it’s the final qualifier that the golfer uses to give a club a thumbs-up or down. Pro golfer Rick Shiels on his YouTube channel recently demonstrated, with great pleasure, hitting a vintage Karsten persimmon 1 wood. The video ends with Shiels taking a final swing, excitedly stating, “What a thud, what a crack.”[i] While laminated wood doesn’t have the same sound of an optimized metal driver, the sound of the vintage club is a truly exciting thing to experience first-hand. Viewers can clearly tell he didn’t want to put the club down. Comparatively, in another review, Shiels’ tester Rob Potter reflects on the return of great acoustics stating “it’s the sound that we want.”
All golfers know that the golf swing is quite complicated and can take years to master. But when physical coordination and equipment align to produce that “crushed” drive you get a pleasing and exciting audible reward. For players tuned into the “right sound,” the emotions associated with that keep the golfer engaged, thinking about the next shot, and returning again and again to the wonderful recreational pastime of golf.
The authors would like to thank Rebecca Dengler PGA Pro for her contribution to this article.
* Roberts, J. (2005). “Evaluation of impact sound on the ‘feel’ of a golf shot.” Journal of Sound and Vibration, 287 (4-5), pp. 651-666.