The next big re-invention happened with Achtung Baby (1991), a grungy, desperate, distorted affair that was produced by Lanois, with help from Eno. U2 have trodden carefully between these two extremes, first changing direction from their early, raw sound with the more intimate and colourful The Unforgettable Fire (1984), produced by Brian Eno then with The Joshua Tree (1987), which featured a more rootsy sound, and was produced by Eno and Daniel Lanois. The Rolling Stones will sound forever like, well, The Rolling Stones and David Bowie has changed his style so many times that he’s alienated and bewildered many of his fans. Other bands and artists with long careers have found different answers to the tensions between commercial demand and artistic renewal.

This is quite an amazing achievement, given that it’s now 20 years since the quartet first met in Dublin, and 17 years since they burst onto the international stage. Everybody knows that U2 have always believed regular re-invention to be an absolute necessity, and the way they have maintained their adventurous musical spirit, whilst still sounding undeniably like U2, has contributed greatly to their continuing critical and commercial popularity.

How many times is it possible for a band or an artist to successfully re-invent themselves? Is there a point beyond which one is doomed to repeat oneself, because another re-invention means losing an established musical identity? Is it necessary to keep re-inventing oneself at all, or is it acceptable to coast along, regurgitating a successful formula, purely for the pleasure of the fans and one’s own enjoyment? And by what criteria is a re-invention judged to be a failure, or a success? These questions have been given new relevance and received new answers with the arrival of U2’s latest album, Pop. To this end, they brought in production wizard Flood and Scottish dance artist Howie B and set about new methods of recording. U2 have always striven for a new sound on each of the records they make, and during the sessions for their latest album, their aim was once again ‘to construct a new sound for U2 whilst still making them sound like U2’.

Multitrack the strokes