In a vast north London production suite that's favoured by stars such as Kylie Minogue and Peter Gabriel, the sublime strains of Pink Floyd's The Great Gig in the Sky ring out. The assembled crowd is rapt, pristine quadraphonic sound and innovative, Pixar-like 3D effects enlivening the flawless playing of those on stage. There are also swathes of laser beams, these bringing a queasy green hue to the face of a giant marsupial that's bobbing up and down behind us.
Roos aside, the Australian Pink Floyd Show tribute act is a deadly serious business. With three million concert tickets sold across 36 different countries, it is also a highly lucrative one. Some 22 years after they formed in Adelaide as "Think Floyd", TAPFS are about to embark upon another European tour. But perhaps what's most interesting about them is the way they blur the lines between tribute act and bona fide band.
For starters, tonight's dress-rehearsal performance at LH2 studios in Ealing was preceded by the kind of swanky reception one normally associates with original acts on major record labels. The plot really thickens, though, when you consider that the Aussies currently employ the sound engineer Colin Norfield, the drum technician Clive Brooks and the booking agent Neil Warnock, all of whom have worked extensively with the real Pink Floyd.
"I'm doing David Gilmour's solo shows these days," says Norfield, "but I love working with the Aussies too, because they understand the power of Floyd's music and we have all the technology we need to pull off a great show." The sense that TAPFS have clout and pulling-power way beyond that of other tribute acts crystallises when you note that the aforementioned 3D visuals are by John Attard, best known for his work on Harry Potter and the Philosopher's Stone. The idea, TAPFS say, is to think, "What innovations would Floyd be using if they were touring now?"
"People say we've elevated ourselves above the tribute thing," says Colin Wilson, the Aussie Floyd's bassist and co-frontman. "I don't know about that, but what might be different is the amount of time and effort we've put in. Some musicians seem to think that the tribute thing is a way to make an easy buck, but if you want to do it really well it takes dedication. It's gone way beyond a hobby or a dressing-up thing for us - there's a lot of attention to detail."
Impersonating someone else, though - isn't it an odd existence?
"It is a strange way to make a living," Wilson agrees. "But we obviously fill a gap in the market. There are an awful lot of passionate Floyd fans out there who want to hear the music played live. We think of Floyd's music as 20th-century classical music, and that's how it will be seen in years to come. I suppose it's a bit like being in an orchestra that plays Mozart every night."
As TAPFS's guitarist Steve Mac (think David Gilmour to Colin Wilson's Roger Waters) has explained, there's a good reason why his band and other long-lived Australian tribute acts such as Bjorn Again (Abba) got ahead of the game. The country itself is so far-flung and tricky to traverse in a financially viable way that, even today, major rock acts tend not to tour there. When they were still working out of Adelaide, TAPFS were able to cash in on this fact, slowly honing their performances while accruing the finances and know-how they would need to take an increasingly elaborate production overseas. "We knew we had the music down, but we always felt this huge pressure to do something that was striking visually," says Wilson. "That's what makes it Pink Floyd."
Another factor in TAPFS's success has undoubtedly been the big thumbs up they have received from the real band. In September 1994, when they played a show in Croydon, south London, the Aussies were thrilled when the Floyd guitarist David Gilmour showed up unannounced. Gilmour was so impressed that he later booked TAPFS to play at his 50th birthday party. "It was all very hush-hush, but to have that kind of acceptance gave us a huge boost," says Wilson of the private event which saw Floyd keyboardist Rick Wright join the Aussies for a take on Comfortably Numb. "We never expected that opportunity; we felt like apprentices playing for the masters."
Instead of resting on their laurels, TAPFS continued to invest and fine-tune. In 2001, when they played at the Royal Albert Hall, their aforementioned attention to detail led them to recruit a choir from the Islington Green Academy, the same London school attended by the children who sang on Pink Floyd's Another Brick in the Wall, Pt 2. When TAPFS returned to the Royal Albert Hall in 2007, moreover, Floyd's Roger Waters was reportedly in the crowd. (Although if the curmudgeonly genius behind the landmark masterpiece The Wall was present, he didn't make himself known.)
The more one dissects TAPFS, the more they look like a tribute act apart. But for better or worse, one of the things that distinguishes them is a rather grave and trainspotterish obsession with verisimilitude. Most of the 200-plus outfits currently registered with the UK tribute act agents Psycho Management still have day-jobs, but they do appear to be having fun. The Antarctic Monkeys, Robbing Williams, Fake That - these are acts whose playfulness begins with their names, then extends to game, though not always convincing costumes.
To be fair, Pink Floyd's material doesn't really lend itself to a frothy approach. Consider the lyrics on The Dark Side of the Moon, a record variously concerned with war, madness, mortality and financial greed. Nor, for that matter, would it make much sense for the Aussie Pink Floyd to dress up like Waters, Gilmour and co, a less-than-flamboyant bunch who have managed to remain relatively faceless despite selling more than 200 million albums. If you have the budget and the musical chops, as TAPFS do, Pink Floyd are actually the ideal act to pay tribute to. Their fan-base is huge, and punters are used to focusing on the band's music, cover art and stageshow, rather than Floyd themselves.
One thing that can't be faked, though, is the original band's potent relationship with its own material. When Waters sings Shine On You Crazy Diamond, a Floyd co-write about their late bandmate Syd Barrett's descent into mental illness, he is drawing upon memories and feelings not in the public domain. It's that kind of unbridgeable divide, perhaps, that leaves this writer somewhat unmoved by TAPFS's performance. Pink Floyd's drummer Nick Mason, however, undoubtedly better placed to comment than I, has described the Australians to the BBC as being "very good. Probably better than we are!"
But what about their own musical ambitions, I ask Wilson? Aren't TAPFS tempted to slip a couple of original songs into their set?
"When we jam in the studio it does inevitably sound a bit Floyd-y," smiles the bassist. "I think putting our own stuff into the set would be a bit taboo, though."