What’s going on when I’m playing music I’ve known all my life – playing it either in my head or in iTunes? It’s something quite different from when I’m listening to something new; it’s a kind of comfort, a predictable sequence, a memory test I know I’ll pass: every lyric, every inflection, every percussive emphasis and fill – all these play back in their precise order and on cue. Detailed familiarity – not exactly relaxing, but giving some kind of comfort. Which is where tribute bands come in, for these Aussies the other night at the O2 did something the real Pink Floyd wouldn’t do – copying, live, every beat, tone and colour of the studio album. The first part – a playthrough of Dark Side of the Moon in honour of its 40th anniversary, matched to a perfect level my parallel mental track (all I noticed different was the guitar/falsetto game at the end of “Money” became guitar/guitar). The projected images were nicely updated: partly Australian jokes and partly filmclips cleverly kept in the early 70′s. The rest of the concert kept a disciplined, beautifully slavish adherence to the original; just in the encore the singer in the middle allowed himself “cannot” for “can’t” – tiny, but through its uniqueness it had the power of the raised voice in the last verse of Tom Waites’ “Missing You”, a tiny release of suppressed emotion which all by itself inspired Kazuo Ishiguro’s The Remains of the Day.

Cover versions are fascinating in their bringing together of the old and the new: one’s mental track has to sit with, to absorb, newness, in the way some literature (all literature?) more or less openly derives from older works. New wine in old bottles.

But carbon-copy tribute versions can bring new flavours: hearing Dark Side like this made me realise for the first time perhaps the way it deals with death as much as with madness: what else is “The Great Gig in the Sky”? And “Breathe (Reprise)” – at the end of “Time” – always reminds me of death – the church and the fields for me evoke the end of Larkin’s “Days“. And the album’s dramatic focus, revealed at this concert by the staging as well as by the song itself, is clearly the sequence of “Us and Them”, the musically most challenging “Any Colour You Like”, and “Brain Damage”, where we get the self-referential

And if the band you’re in starts playing different tunes
I’ll see you on the dark side of the moon.

Then we are left with the more straightforward build-up to the climactic triumph of lunacy in “Eclipse” (“But the sun is eclipsed by the moon”) – Sid’s back.

The concert then had bits of the Wall, the whole of “Echoes” (I’d never before realised the urgent and pressing power of this song’s vocal line), some later songs I didn’t know, before ending with “Comfortably Numb” and, as encore, “Run Like Hell”. “Comfortably Numb” was done well, its nostalgic lyrics of childhood still powerful (Lawrence’s “I weep like a child for the past”).

But what got me most that evening were the three female singers – wonderful backing voices, stellar as leads in “Great Gig” – but the way they moved… a range of choreographed hand and arm gestures, fitted perfectly to each part of each song, and making them look like mermaids or sea anemones. OK – they were, in theory, sexistly conventionalised candy (the men wore tee shirts and stood motionless, the girls changed dresses every song or two and were constantly gyrating), but as it was they were theatrically more than that: have a look.