Ever since Eric Clapton and Jimi Hendrix popularized the wah-wah pedal – a foot-operated device that derives its onomatopoeic name from the reverb sound it creates – guitarists have used their toes to do more than tap along to the beat. Now, a gadget called the Hot Hand allows axe-men to create the same effect by wearing a Green Lantern-like ring on their picking hand. "Those motions you can make with a foot on the wah-wah pedal are not really quite the same as what you can do with your hand while you're strumming the guitar," explains Bob Chidlaw, chief scientist at Source Audio in Woburn, Mass., where spontaneous guitar jams are all in a day's work.
The digital device relies on a wireless transmitter to translate the guitarist's hand motions into a wah-wah sound (for a demonstration video, visit sourceaudio.net). The traditional wah-wah pedal, connected between the guitar and the amplifier, alters the pitch of the signal. But the pedal, Mr. Chidlaw says, only has a single peak in its frequency response, whereas the digital Hot Hand can create multiple peaks and multiple dips to attain "a very vocal sort of sound."
Oddly enough, guitarists can thank air-bag sensors for the technology. The Hot Hand is really an adapted accelerometer chip that measures the acceleration of the hand movement to modulate sound. "You can be a lot faster with your hand in terms of how you modulate the sound," says Chidlaw. In other words, you'll need to be a lord of the ring to become a lord of the strings.