Callaway Golf was the first company to use medallions on the back of 1993 Big Bertha iron to dampen the sound made when the oversize, thin iron face hit a golf ball. Since then many club manufactures have designed irons with medallions on the back of the heads to soften feel, dampen vibration, improve consistency, lower the center of gravity or simply make the club look good.
Every Ping iron made today has a medallion. The medallion in the G10 is more noticeable than the one in the S57, but both are designed to dampen vibration and improve feel.
The thinner faces on the cavity back, cast heads can include inconsistencies that affect distance control and ball velocity. Medallions help stablize the clubface and reduce the effects of these inconsistencies. The result is a set of irons that all feel alike (more or less).
Game irmprovement irons have similar design elements that include medallions, some filling the entire cavity of the clubhead. Callaway was also the first to use a full back-cavtiy medallion in the X-14 iron.
The medallions on most pro-line irons are positioned very close to the natural center of gravity of the head. In the case of game improvement irons, the medallion can help get the ball in the air.
Medallions are made of foam, elastomer, urethane or other material that controls and modifies vibration. In some cases the medallion allows mass distribution farther back in the clubhead, which reduces twisting at impact, anther “forgiveness” feature.
The medallions on inexpensive irons are usually cosmetic and don’t effect performance.
