In two months' time the Royal Festival Hall will reopen to all the usual royal hullabaloo. Most of what will be on show has been trumpeted in advance: the restoration of many of the original 1950s design features that previous refurbishments have altered or covered up, hugely enhanced front-of-house facilities for concert-goers - including shops, restaurants and bars - and state-of-the-art accommodation for performers backstage.
What remains the biggest unknown quantity, though, is what the hall will actually sound like - whether the money spent will finally give London a concert hall with truly world-class acoustics, an auditorium that enhances great performances in the way that the Concertgebouw in Amsterdam and the Musikverein in Vienna do.
An improvement on what was there before seems virtually guaranteed, however. The dry, unforgiving sound of the RFH before its closure in 2005 was only tolerated by those who performed there regularly, and effectively discouraged several of the world's leading conductors from visiting London more often. Yet though designing concert-hall acoustics is big business nowadays, it still seems as much an art as a science, for all the advances in computer modelling, and the huge range of materials that can be used to modify the results. Though I'm sure those who have had responsibility for fine-tuning the Festival Hall's acoustics over the last two years have a good idea of what they have produced, I'd bet that until the first concert takes place with a full orchestra on stage and a capacity audience, there will be a little apprehension about whether they have got the recipe exactly right.
Even if everything turns out as planned, though, it's a fair bet that not everyone will be satisfied. Britain currently has just one hall whose sound seems to get universal approval. That's Symphony Hall in Birmingham, which was exactly the right combination of analytical clarity and tonal warmth, and whose resonance can be adjusted to suit whatever is being performed.
The other halls built recently in the UK have been much more hit and miss. The sound of the Bridgewater Hall in Manchester has certainly been improved since it opened a decade ago - everything is much more focused now, if still not particularly alluring. That of the Royal Concert Hall in Glasgow, though, still leaves a lot to be desired, while the changes made to the Barbican in London during its recent renovation have certainly made its sound more immediate, but has also given it a rather brassy edge that can make even the most refined orchestras like the Royal Concertgebouw and the Berlin Philharmonic sound raw and raucous. What we'll get at the Festival Hall, then, is impossible to predict.
