A cultural triumph or a white elephant? As the Sage Gateshead, the culmination of a 40-year dream, prepares to open its doors on Friday, its director tells Nick Morrison why this is just the start of a musical journey.

ANTHONY Sargent doesn't seem like a man approaching the moment of truth. He's between a seemingly endless round of meetings in the build-up to the big day, workmen are still applying the finishing touches to the building, staff are undergoing last minute training around him, but at the centre of this maelstrom, in a bistro still half-covered with plastic sheeting, he sits apparently relaxed, calm and exuding confidence.

As general director of the Sage, he knows the crunch time is almost upon us. In two days time, the much-talked about music complex will open its doors, and the public will get its first chance to judge if the £70m investment has been worthwhile.

Certainly the building has already won plaudits. Designed by Norman Foster, its giant curving roof ripples like an armadillo on the move, completing a cultural trio, alongside the Baltic arts centre and the Millennium Bridge, which has transformed Gateshead Quays.

But Sargent knows it is what takes place inside the building that will determine if it is hailed a cultural triumph, or whether it will sit forlornly by the Tyne, its gleaming silver panels decaying to reveal another Lottery-funded white elephant.

And his confidence is not without foundation. When the Sage opens on Friday, it will be the culmination of years of meticulous planning, a clever marketing campaign, and, above all, a belief in what it is trying to do.

"This building is the expression of the vision for a new approach to music, that looks right across the board, that sees education and performance as equally central," says Sargent.

"It is not just about giving audiences pleasure, but it is building the artists of tomorrow and developing a real sense of interest right across the musical map."

The Sage was born from the desire to build a concert hall to rival the best in the world - including giving the Northern Sinfonia a home for the first time in its 46-year history - and create a school to encourage talented musicians to stay in the North-East.

But the musical traditions of the North-East dictated that a classical venue on its own would be insufficient, and that other strands, particularly folk, should have equal billing. And once it became clear that any new venue would host different types of music, then it became obvious that one hall was not enough.

The result is two main halls, one 1,700-seater built to the same shoebox design as the Musikverein in Vienna, widely regarded as the best in the world, the other a ten-sided affair which seats up to 450, depending on how it is configured, with a rehearsal room in between. Below are around 20 teaching and practice rooms, as well as a recording studio.

For Sargent, the two main halls are a sign that the ambition to be more than just a classical music venue is no hollow boast.

"If you are serious about this, about folk music or jazz being as important as classical, then one space is not going to do this. You need to have different sizes, different shapes," he says. "If you are going to have a full range of music, then one space isn't enough."

But giving equal billing to different types of music, and the brochure lists concerts by date and not genre, risks creating an impression that the Sage dabbles in everything but specialises in nothing.

Sargent is well aware of this risk, but insists the Sage is different, by means of an unusual analogy.

"What does Harrods specialise in?", he asks rhetorically. "They have as good a food hall as anywhere, but their made-to-wear clothing is fantastic. We have a very clear idea of what Harrods means, but it isn't defined just by food or clothes.

"It is the range of what they do, the quality of the merchandise, the quality of the service and the reception you get when you go in the doors. You pay a little more at Harrods and that is where the analogy breaks down. Here you pay a bit less."

Indeed, with tickets starting at £6, the Sage's prospects appear good, and advance bookings total around the half-million pound mark, with annual turnover expected at £12m. Sargent's confidence is also backed by extensive market research, which suggests there is a market of around 1.2 million people who will go to the new venue, even in an already crowded pool.

But he acknowledges that the biggest resistance to bringing different sorts of music together has come from the Sinfonia's loyal following.

"People didn't think the other audiences would be precious, but there was quite an anxiety that the classical audience, that has quite specific tastes, would feel that the cherished jewel of the Sinfonia would be identified with a very different scene.

"It was probably the single thing we were least confident of how we would solve it. We have got to treat these people with complete honesty and not patronise them, but on the other hand, we must not compromise and give them a sense that classical music will have its own enclave," he says.

To some extent, he is relying on his 30-year track record in classical music to persuade the Sinfonia's audience to trust him, but an extraordinary attention to detail has gone into the programming to avoid alienating this loyal core, even down to the sort of music playing in the concourse when a concert finishes.

"I would not bring people out of the Bach B Minor Mass into a rock concert, but I might bring them out to chanting from Buddhist monks; coming out of the Rite of Spring, I would be more confident about bringing them out to a rock concert; coming out of Mozart, they could hear some highly structured jazz, such as Dave Brubeck.

"The experience of coming out into the concourse could be really inspiring and interesting, but if you get it wrong it could completely undermine the last two hours," he says.

The umbrella body, North Music Trust, which includes Folkworks, the folk music body which runs the Sage with the Sinfonia, has also staged a series of concerts at venues across the North-East. Beginning with trumpeter Wynton Marsalis in February 2001, these aimed to identify the new body with quality, to establish trust in its programming, and to create a familiarity with the Sage before it even opened, building up a healthy mailing list in the process.

These concerts have also aimed to encourage devotees of one particular type of music to try another for size, and it is the success or otherwise of this strategy that will determine whether the Sage fulfils its mission: not just to provide a new venue for music, but to create a musical melting pot, where folk musicians rub shoulders with classical maestros, where young flautists pick up the Northumbrian pipes to have a go, and where it's a toss-up for audiences between a Haydn concerto and a saxophone quintet. Maybe some will try both.

"I think people make these journeys in single steps, and you can try and make a step as big as you can, but we won't try and make it too big," he says. "People are going to look carefully at our programme and see it is a serious programme and it is about quality, not volume.

"I have come to this project to treat all different kinds of music with the same respect and dignity and seriousness. There may not be an enormous country and western audience, but the audience there is will expect us to put on the best country music that there is. To some extent people are going to have to trust me."

Sagacious statistics

The £70m Sage won the biggest arts Lottery grant in the country outside London, £47m.

The curved roof contains 720 tons of steel and 3,000 stainless steel roof panels, with a total area of 10,500sq metres.

The external structure gains no support from the halls, to ensure they are acoustically isolated.

At 8,584sq metres, the building covers the same area as two football pitches.

Gateshead Council won a competition to site the new centre in 1996, with building work starting in 2001.

A 100-metre ribbon of coloured glass designed by Kate Maestri runs along the front of the concourse.

Hall One has an adjustable ceiling, sound-absorbing curtains and a panelled wall to heighten the acoustics.

An air-diffuser under each of the 1,700 seats supplies air to the auditorium silently, to avoid an air-conditioning system from compromising the acoustics.

Business software supplier the Sage Group secured naming rights for the new venue for £6m.

At £11.65m, the Sage's endowment fund, which covers the venue's running costs, is the largest of its kind in the country, and more than 90 per cent of it was raised in the North-East.