News that Pink Floyd will return with new music based on ambient sessions from 'The Division Bell' era sent us back to David Gilmour's atmospheric collaboration with the Orb from four years ago. Nick Mason, who has been working to complete the forthcoming 'The Endless River' with Gilmour, has already compared these never-before-heard early '90s Floyd sessions to the Orb's earlier ambient explorations.

In that context, 2010's 'Metallic Spheres' provides us with hints as to what this forthcoming Pink Floyd studio project -- the last to feature work from the late Rick Wright -- might bring. The Orb album itself also represented an interesting career moment for Gilmour, who has sometimes struggled in the post-Roger Waters era to remake Pink Floyd in his own image.

Listen to 'Spheres' by the Orb with David Gilmour

In a way, the Orb's signature sound -- gorgeous but not quite ambient, hypnotic but typically not much more rhythmic than a chill-out room -- seemed to cry out for a central instrumental voice. And, specifically, one like Gilmour's.

The band copped to Pink Floyd's underlying influence on its debut album, 1991's 'Adventures Beyond the Ultraworld,' the artwork of which prominently featured the Battersea Power station -- echoing the cover of Floyd's 1977 recording 'Animals.' Alex Patterson of the Orb then remixed two different versions of "Runaway," from Wright's 1996 'Broken China' album.

Finally, the Orb -- Patterson and producer Martin "Youth" Glover (who will also serve as co-producer on 'The Endless River') -- completed the circle, combining the British group's now-familiar deconstructionist sound collage of tribal/trance refuse with one of doob-rock's most recognizable instrumental touchstones on 'Metallic Spheres.'

Gilmour's familiar Fender Stratocaster vibrato effortlessly blended with the Orb's next-galaxy synthesizer washes, mid-tempo house flourishes and whoa-man effects. Along the way, it helped both Gilmour and the Orb reclaim a measure of their own early promise.

After years of wandering through what can only be described as a post-rave wasteland, the Orb belatedly re-emerged with a winning new techno amalgam -- Floyd-meets-dubstep? -- on 'Metallic Spheres.' Meanwhile, setting aside Pink Floyd, with all of its history and expectation, sparked something primordial in Gilmour. In a place with no boundaries again, Gilmour recaptured a youthful vibrancy -- far more in keeping with his free-flowing asides on 'Atom Heart Mother' and 'Meddle' than the pent-up frustrations of Waters-dominated albums like 'The Wall' and 'The Final Cut.'

Thereafter, Gilmour would work alongside a series of lyricists and co-writers in Waters' absence, notably wife Polly Samson, but only achieved mixed results under the Floyd moniker. The fault, as 'Metallic Spheres' makes clear, lay in focus rather than intention. 'Metallic Spheres' sent him further back, past unrepeatable triumphs like 'The Dark Side of the Moon,' to a turn-of-the-'70s moment when he excelled in pensive, narrative instrumental musings. That return to his own roots hurtled Gilmour, finally, past an impossible talisman.

Gilmour-as-Floyd was never going to top 'Dark Side,' and certainly not without Waters' biting lyrical wit. Besides, several elements of the ambient house/techno movement that the Orb helped define actually sprang from the earlier era of Floyd performances. So 'Metallic Spheres' did more than make musical sense. It illustrated how Gilmour could have -- and, with the arrival of 'Endless River,' could still again -- definitively claim a new Pink Floyd legacy for himself.

Listen to 'Metallic' by the Orb with David Gilmour

If the two-part recording -- broken up into the "Metallic Side" and the "Sphere Side" -- occasionally sounded like it hasn't been fleshed out quite enough, that's because it actually grew out of a charity single Gilmour was working on with Youth. Gilmour left behind a series of unconnected guitar snippets, for which the Orb then created sound beds. So, there are a few moments when his solos -- at their best, these whole-step bending, backward-grace note-sliding wonders -- fail to rise to the level of Gilmour's most recognizable work with his old band.

It's easily forgiven, however, because 'Metallic Spheres' not only represents one of the more compelling blind alleys Gilmour ever turned down, it points the way (we're now learning) toward one of the most unlikeliest moments in Pink Floyd history: A new studio album, 20 years after the last, and nearly six years after Wright's death -- a sad moment many assumed signaled the end of the band's second-era, Gilmour-led lineup.

And, perhaps, their return to a free-form, opened-ended Pink Floyd sound we haven't heard since Waters' ascension.

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