The multi-million pound transformation of the Royal Festival Hall on London’s South Bank has been unveiled. Allies and Morrison’s two-year, £100m revamp of the Royal Festival Hall (RFH) on the South Bank has restored the Grade I listed building to its former glory.

“The Royal Festival Hall holds a unique place in the cultural life of this great city,” said Clive Hollick, chairman of the Southbank Centre. The 2,788-seater auditorium now has upgraded acoustics, under-seat air conditioning and increased leg-room.

For years, musicians have complained about the quality of the sound. Now the Southbank’s directors are confident they have a concert hall fit for the world’s greatest artists to perform in. Visiting orchestras have long had to tolerate the flat acoustics. Berliner Philarmoniker composer Simon Rattle allegedly once said that within 30 seconds of playing there, he lost the will to live.

Staff and production facilities have been moved into a new extension building, creating more space in the hall for public use. Interval bars have doubled in size and outdoor balconies now provide panoramic views of the river Thames.

“It is wonderful that one of London’s brightest stars is back and ready for business,” said Culture Secretary Tessa Jowell. “It does brilliantly and simply what many people in the cultural sector aim to do – ensure that world-class events are enjoyed by as many people as possible, in a fantastic and inspirational setting.”

To mark the opening, 24,000 free tickets will be handed out for performances on 9 and 10 June ahead of the First Night Gala Concert the following Monday. Massed choirs will arrive by candlelit river boat for the opening celebrations on 8 June.