In 2007, a new type of golf club hit the market. The distribution of mass in the club head made it less likely to twist, making an off-center hit less likely to send the ball veering off course. It did have one drawback: a loud noise when it struck the ball, piercing through the tranquility of a golf course. The club never grew popular among players, with many saying they disliked the noise. "Some players compared the sound to a cookie tray hitting the top of a car," said Daniel Russell, a professor of acoustics at The Pennsylvania State University. "It was such a different -- some say annoyingly loud -- sound, it raised eyebrows."

Russell and his graduate student Peter Kerrian set out to find the cause of the offensive clang. They had analyzed a variety of clubs from recent years and the "noisy club" stood out as a particularly interesting test case.

The researchers tracked the clanging sound to vibrations in the bottom of the club head, called the sole, that were strongest in the most sensitive range of human hearing. 

The researchers will present their results at the 171st meeting of the Acoustical Society of America, held May 23-27 in Salt Lake City.

Russell has long studied the acoustics of sports equipment, including baseball bats, tennis rackets and hockey sticks. He says sound is one of the major considerations for players in selecting equipment. "They want to hear the sound and be able to get a sense of the quality of the hit," he said.

In the case of the new driver, the sound not only didn't match expectations, it annoyed people.

"The sound had peaks in the 2-3 kilohertz range. The human ear is very sensitive to this range," Kerrian said. He compared the sound to the tin-can ping of an aluminum baseball bat, another grating sound for sports aficionados.