Because what usually elicits the comment, "Great swing!" is an image—a smooth, on-plane motion that produces a great result— professional golf instructors concentrate on the picture of perfect swing mechanics. They suggest visual and physical cues to tweak all your body parts—hands, arms, shoulders, hips and legs—at address, in the backswing and downswing, at impact and follow-through. Most teaching devices do the same, tracking the path of your swing, holding your arms in fixed positions with a contraption or recording your swing on video to be overlaid on that of Tiger Woods—always a depressing moment. What none of them do is to stress another integral, but harder-to-see quality of a great swing: a consistent tempo.
Enter Sonic Golf, the first instructional golf aid to address swing rhythm, using audio cues as feedback. A transmitter attached to the grip end of your club sends a signal to a receiver attached to your belt, which translates the motion of your swing into a "soundscape" that is relayed to a pair of ear buds. The faster the swing, the louder and higher pitched the sound. Listening to that auditory portrait you can concentrate on creating your swing's highest velocity in the optimal power zone: at impact and just past the ball. Perhaps more importantly, the device captures the instant of the set at the top of your backswing: at that point there is no sound, thus making it possible to concentrate on that transition from backswing to downswing.
While I found the device lacking in comparative benchmarks—i.e., an easy guide for what the best swing would sound like—it did help me focus on one of my many swing flaws—a hasty transition at the top of the backswing. Better yet, I was able to take that feeling created by hearing the silence, and carry it over to a club without the transmitter.
Setup is a bit complex (best left to your pro), and like any device Sonic Golf isn't a panacea. But if you use it to key in on matters of rhythm and tempo, your swing will be the better for it.