For me, the tone was set by the gloomy, slightly sinister new entrance sunk like a cavern in the old façade. It was meant to be light and joyful: instead, it is Stygian. The original architects went bust, and the work was completed by Burrell Foley Fischer, whose work is normally better-resolved than this. Interior design is by Peter Mance, who used to work for designer Ben Kelly of Hacienda club fame. I can’t say it wowed me, inside or out. True, I was there in the cruel, empty daylight. Such places come alive when they’re lit up (Ocean has video-projection windows) and packed out at night. On the other hand, it’s also used a lot during the day and will form part of Hackney’s arts quarter along with the refurbished Empire and the new library, now being built. These buildings together comprise a civic square. Much more could have been made of Ocean’s physical presence - but then again, that would have required a much bigger budget.

At the opposite end of London, and nearly but not quite at the opposite end of the musical spectrum, is the newly-opened Bush Hall in Shepherd’s Bush. Where Ocean cost £23m, Bush Hall cost a few hundred thousand to convert from its previous use as a snooker hall. The 1904 building was originally the Carlton Ballroom, and its richly-moulded plasterwork is full of musical motifs. Run as a members-only private venture by classical and modern jazz enthusiasts Charlie Rayworth and Emma Hutchinson, it seats a maximum of 150 people - arranged not in rows of seats a la Wigmore Hall, but cabaret-style at tables. Performances often take place in the centre of the space rather than end-on.

You know the moment you walk in that this place is a real find, a happily-preserved piece of Edwardiana. Rayworth and Hutchinson, who also run the Music House childrens’ educational charity from an office above the hall, have so far done little more than necessary light repairs - apart from some heavy investment in traditional chandeliers. The red-carpeted venue is feeling its way, aiming to do no more than break even at the box office, and to subsidise performance with profits made from catering and private hire. The autumn programme will consist of just two concerts a week. Typically you’ll find a good piano trio or jazz quartet, though they have dabbled with percussion and acoustic folk. It deserves to become a cult rendezvous.

With the Wigmore now spruced up after its centenary celebrations, London’s eyes now turn to the big one: the 1951 Royal Festival Hall. A £60m upgrade programme is planned there over several years, starting this autumn by opening up the blocked-up backside of the building. Around 2005, work begins on radically improving the acoustics of the now shabby auditorium. Eventually, all the South Bank Centre’s offices will be decanted into a new building by the railway tracks alongside - so releasing the whole of the listed Festival Hall to the public, including its forgotten roof terraces.

As part of this ambitious programme - masterminded by architects Allies and Morrison - smaller performance spaces will be rediscovered, such as the Hall’s under-used ballroom, or the 200-seater lecture room/theatre now occupied by the Arts Council’s poetry library. Of course, the idea is also to build a new 1100-1500 seater further concert hall on Jubilee Gardens next door as part of the South Bank’s greater masterplan - a size up from the 900-seat Queen Elizabeth Hall on the other side, which may or may not remain. After much delay, architects are due to be announced in September.

Then again, just this type of second auditorium has been planned for the South Bank ever since the RFH was originally built. Who knows? One day it may even happen. A curious paralysis always grips such state-subsidised high-art venues. Had this been deemed non-elitist, of course, it would have been built by now. And it has been. In Hackney.