It took a crack team of sound engineers armed with a reflector microphone, a bassoon and a starting pistol to solve one of the UK’s most enduring engineering challenges – the Royal Albert Hall echo.

jpg(Acoustic tests in the Royal Albert Hall, 19969

Although the echo was identified at the time of the first acoustic tests in the Hall, on 26 February 1871, this issue that was not addressed properly until well into the 1960s.

The saying went that concertgoers heard a concert two times for the price of one, due to an unfortunate problem with reverberation – the giant expanse of empty space and glass roof of the auditorium caused the Hall to have an horrendously long echo. Between 1871 and 1968 various methods were used to try and muffle the tremendous echo that reverberated around the auditorium, but without much success.

velarium in the Royal Albert Hall roof
The huge cloth ‘velarium’ was an early attempt to muffle the echoes in the Hall

In 1968, the Acoustical Investigation Research Organisation Limited surveyed the acoustics in the Hall with several tests, one of which involved an acoustic technician using a reflector microphone whilst another fired a starting pistol and another played the bassoon. On their advice, 135 ‘flying saucers’ filled with glass fibre wool were suspended above the arena to diffuse the reverberations.

The first concert after the diffusers were installed was performed by the BBC Symphony Orchestra, conducted by Colin Davis. The acoustics had improved noticeably and were greeted with enthusiasm by the press.

The Royal Albert Hall 'mushrooms', 2013

There was one final tweak in 1996, after Dutch company Peutz & Associates conducted experiments on a 1:12 scale, 4 metre long model of the auditorium. Miniature loudspeakers were used as sound sources and microphones were built into headsets worn by Barbie dolls to monitor sound at strategic positions! They discovered that a reconfiguration and removal of some of the now famous ‘mushrooms’ would significantly improve the sound quality once again. The reconfiguration was completed in December 2001, condemning the Hall’s negative acoustics to history.