When the Who initially attempted to tour Quadrophenia in 1974, the results were a disaster. The band performed the rock opera alongside a series of backing tapes containing synthesizers and sound effects, a decision that put the mercurial Who into a straitjacket and led to uncharacteristically restrained performances. For years, the legend that Quadrophenia didn't lend itself to the stage persisted but things started to change in 1996, when an all-star production was launched at London's Hyde Park. This was such a rousing success that U.K. and U.S. tours followed and, from that point on, the Who returned to Quadrophenia far more often than Tommy, which they essentially retired after it turned into a Broadway musical. Anchored by a July 8, 2013 performance, 2014's Quadrophenia: Live in London pays tribute to the enduring legacy of Pete Townshend's rock opera. The concert is available in a variety of iterations, the simplest containing nothing more than the 2013 show -- this is available as a double-CD set, a Blu-ray, and a DVD, plus a digital download -- the most lavish being a five-disc box that contains the concert in the CD, Blu-ray, and DVD formats, along with the first-ever 5.1 mix of the original 1973 album, a feature many fans wish was included in the 2011 deluxe box set reissue of the album (there, only eight songs were mixed into Surround). If there ever were a record that cried out to be remixed in 5.1 Surround Sound, it's Quadrophenia -- it's enveloping enough as stereo, but the synths and sound effects beg for an immersive experience -- so this mix (which is also available separately as a Blu-ray Pure Audio single disc) is a worthwhile enticement on its own terms, but the 2013 show is strong on its own terms, too. Working with their longtime touring band of drummer Scott Devours, bassist Pino Paladino, and rhythm guitarist Simon Townshend, Pete Townshend and Roger Daltrey are tight and assured, substituting a weathered gravitas for the original's roiling teenage angst. Neither singer can hit the high notes he did in the '70s but neither tries, and their deeper voices add a sense of melancholy that contrasts well with the vigorous muscle of the band. An encore of greatest hits (plus "Tea & Theatre," from 2006's Endless Wire) is a nice touch but the focus is where it should be: on Quadrophenia, which upon its 40th anniversary sounds like Pete Townshend's masterpiece, whether it's heard in its original LP version or on this very good live set.