PERFECT tuning has long eluded the world's musicians: like the yeti its existence is assumed but so far never authenticated. For centuries the 12 standard intervals divided an octave have left players struggling with an imperfect harmonic jigsaw.

Violinists, with wide freedom to control their instruments, make constant tuning adjustments. But pianists and guitar players, working with a more rigid mechanical framework must steel themselves to accept sounds which sometimes come out slightly wrong.

Today, at London's Barbican Centre the curtain is being raised on the Lucy scale, an attempt by a computer-literate guitarist to build on the work of an 18th-century clockmaker. The aim is to remove the fundamental artistic obstacle which forces instrumentalists to play an A sharp as if it were a B flat, when all their instincts shout that they are different.

Charles Lucy, the scale's inventor who often busks on London's Underground, said: "If this catches on, the public will have an alternative system to create music: much more harmonious, much more consonant."

The deficiencies of the conventional 12-tone scale had worried Lucy for years. But his attempts to straighten them out proved fruitless until he discovered the work of John Harrison (1693-1776), inventor of the marine chronometer. After squeezing 20,000 pounds out of the govenment, Lucy devoted himself to perfecting "the really true scale of musick".

It was Harrison's work on the subject, enshrined in the City at The Clockmakers' Library, which put Lucy on the right track. "I took his numbers and equations and worked them through on the computer."

Harrison's discoveries showed that the closest approximation to perfection required the division of a scale into 19 or 25 parts, as opposed to the classical 12. Applied to a guitar, the Harrison/Lucy solution means providing 19-25 fretted divisions. Although careful to point out this is just one of hundreds of variants proposed throughout the ages, Lucy admits: "The difference is, this one seems to work." The Barbican guitar weekend is the acid test.

Darrel Mayers - The Sunday Times 29th November 1987.