Stay tuned

It’s a scene acted out nightly in music venues all over the world. The audience whoops and wolf-whistles in anticipation as the band takes to the stage. The lights go down. The anticipation is palpable. The leonine, Spandex-clad singer grabs the microphone. Then, the spell is broken as the guitarist decides to ‘tune up’.

The out-of-tune instrument is one of the perennial bug-bears of the guitarist. No matter how carefully the instrument is tuned, in the brief window of opportunity between sound check and performance, everything from hot stage lights to accidental knocks from roadies will quickly cause the offending instrument to slip out of tune.

In response to this, guitar maker Gibson has employed the kind of precision technology more usually found in the car industry, to develop what it claims is the world’s first self-tuning guitar — the Gibson Robot.

Launched in a blaze of publicity late last year on a limited number of the company’s Blue Silverburst Les Paul guitars, the tuning system is based on an innovative blend of piezoelectric materials that monitor the frequency of individual strings and tiny servo motors that are able to rapidly adjust their tension.

According to the system’s creator, German engineer and guitarist Chris Adams, the technology will tune the instrument in just a couple of seconds. All the guitarist has to do is pop out the control knob and strum all six strings. Adams, who has been developing the technology over the past 10 years through his firm Tronical, explained that as well as enabling guitarists to stay in tune, users can also store an additional six alternative tunings in the guitar’s memory — potentially ending the theatrical sight of axe-gods working their way through a museum-sized collection of instruments over the course of a performance.

Sold separately under the Power-Tune brand name prior to its adoption by Gibson, the system’s main components are a central control knob, two processors (one beneath the control knob and one tucked away unobtrusively on the back of the neck), a series of tiny servo motors that drive the machine heads (or tuning pegs) and a so-called tune-controlled piezo bridge.

This specially designed bridge — the part of the guitar supporting the strings — contains an innovative piezoelectric saddle that generates a small charge in response to the vibrations from individual strings. The signal from each string is isolated by ceramic insulators, as well as special isolating inserts that keep the ‘ball ends’ commonly found in the end of electric guitar strings from disrupting the signal.

A user controls the system through the master control knob. Pulling it out activates the system, and pushing it turns it off again. In the ‘pull’ position it acts as a rotary switch which, to the probable delight of Spinal Tap fans, enables the guitarist to access 11 settings. The system also contains a number of specially developed multicoloured LEDs that enable the musician to quickly see what is going in the darkest or brightest environments.

During operation, the charge produced by the piezoelectric saddle is transmitted to the main processor unit in the body of the guitar. This uses algorithms to calculate the frequency of each string’s vibration and compares these with the desired notes. This data is then sent to the neck-mounted processor, which instructs the corresponding servo motors on the tuning pegs to tighten or loosen each of the strings by the desired amount.