Welcome to the Metropolitan Opera's 294th performance of Verdi's great middle-period work, Un Ballo in Maschera. The Met, whose grandiose arches dominate the forecourt of Lincoln Centre, seats 3800 (plus 175 standing), which makes it one of the largest opera houses in the world. But these figures are finite: only so many can see opera live.

For hundreds of thousands of others, the company's successful Live in HD series of broadcasts have brought the Met's repertoire to a world far beyond the splashing fountains of Lincoln Centre. For instance, the Ballo matinee performance of December 8 was seen live in cinemas across the US and in Europe; this month, it screens in Australian cinemas.

There are, of course, substantial differences between opera live on stage and projected on a wall. From row M of the orchestra stalls, my Met experience was magnificently thrilling. Primarily, you are there as it happens, living and breathing the performance along with those who are creating or contributing to it. When all the musical and dramatic elements are as one, they fuse into something special, something unforgettable. And so it proved.

The Met Orchestra, that great musical instrument, played passionately and flawlessly under the house's principal conductor, Fabio Luisi. The singers, by this, the third performance, were well into their roles: Marcelo Alvarez's lyrical Gustavo; Sondra Radvanovsky's powerful Amelia; and, as her avenging husband Ankarstrom, the suave and honey-baritoned Dmitri Hvorostovsky. The diminutive soprano Kathleen Kim was an outstanding page, Oscar.

This splendid and focused production of Ballo in Maschera is new. Its director, the American-born David Alden, is making a somewhat belated Met debut. Alden, who works mainly in Europe, has had a long association with this opera, first directing it a quarter of a century ago for the English National Opera. ''It made my career in a way,'' Alden told me back in London. ''In those days, the ENO didn't have a whole lot of money to spend on visuals. So the aesthetic of the production was very different. The show had a raw simplicity.''

The aesthetic of Alden's Met production is, he says, even more refined. It is dominated by a huge Baroque painting of Icarus falling from the sky - an mythological figure Alden associates with the opera's central character, Gustavo III. ''Gustavo is a king who is more of an artist, an effete, and I wanted this obsessive visual image to carry through the piece,'' Alden says.

The censorship of the day forced Verdi to relocate the action of the opera from the Swedish court to the unlikely location of colonial Boston, which Alden calls ''ridiculous, totally wrong for the music and a betrayal of the score''. Although his production is the Swedish version, it is deliberately set closer to our own times.

''The Swedish connection in my head has to do with Strindberg and Bergman. I wanted it to be slightly fractured, with that sense of European government.''

I asked Alden how he felt about the transfer of his production from stage to screen. ''Obviously you gain a closeness to the singers and intimacy with them and what they're doing, if you have singing actors as we do. That's the good news.''

The bad news - at least for Alden, who saw the broadcast a few days before our interview - was how the transition changed what he calls the spatial tension of his production.

''My shows are about people within a space, the distance between and the closeness between people and tension in an enclosed space. I am just as interested in movement and space as I am in psychology. What you got on this one was 99 per cent focus on people and relationships; what you didn't get was the visual and choreographic narrative.''

What was also changed, Alden said, was the lighting. ''That, for me, is everything. Light is the focus and narrative and the closest response to the music that one has to deal with. Obviously you have to change some of the lighting for the cameras, but this was much more than making an adjustment.

''What I don't like was that I wasn't included in the process at all. Everywhere else you have meetings with the director and are consulted about the process, and you can work with them to try to preserve what you had in mind. This was not the case here.''

The general manager of the Met, Peter Gelb, responding in an email, said although the intention was to stay true to the original staging, some ''minimal adjustments'' of lighting were necessary to modify viewing levels for HD transmission. ''The new production of Ballo required more significant adjustments of lighting than is the norm,'' Gelb said.

''Given the practical issues of rehearsing the cameras at a performance on a Tuesday, and re-scripting and preparing for a live transmission just four days later, an in-depth consultation with Mr Alden, who was in Europe during this period, was not possible - although he was sent a copy of the scratch Tuesday tape via computer file in order to provide his comments. While we regret that the results might have been disappointing to Mr Alden, we believe the live transmission was a success in terms of its adaptation for the large screen.''