Memory Flying Saucers

“I’d like you to go over to the Albert Hall. There’s a party on this evening for Stokovsky, who’s in town at the moment. We have a problem there.”

This sounded curious as I had no idea exactly what the problem was. As far as I was concerned, the Albert hall was privately owned and could not therefore receive public money unless it turned itself into a charity.

It turned out that the party was also concerned with the acoustics of the hall which possessed a rather prominent echo and a long reverberation time. I gathered second-hand at the party that Stokovsky had proposed hanging up the flags of all nations from the front of the gallery to defeat the notorious echo and promote world peace.. I also learned a lot about the hall including the fact that even the rooms under the arena were designed along the lines of the colosseum in Rome.

The volume of a hall is one of the main parameters which determine the reverberation time. Simply put, that’s the time taken for the sound to die away. The other main London concert venue was the Festival Hall which – again simply put – had a volume which was too small. The solution to that hall was to provide assisted resonance using a series of amplifiers and speakers which each treated a tiny range of frequencies.

The problem in the Albert Hall was that the volume was very large and there was an echo mainly due to the dome which enabled certain sections of the audience to hear each note twice!

But there was hope. A young acoustician who lived in a basement flat near the Victoria and Albert Museum appeared with a simple solution. When I asked him what he had been doing recently, he told me he had been working on “Acoustic Perfume” for cabins in ships using bands of noise to mask the background engine sounds.

But when he explained his ideas, they were beautiful in their simplicity. He would hang a number of “flying saucers” from the dome which would provide reflection on the undersides and absorption on any reflected sound from the dome on their topsides.

This blew me away – it was SO simple! It takes a certain type of genius to come up with a truly simple solution to a complex problem. Later, when explaining his plan back at the ranch, I described it as a “half ceiling” to the hall cutting off half the sound from reaching the dome. We couldn’t build a whole ceiling – that would not have pleased English Heritage! – but we might get away with a half ceiling in the form of a number of flying saucers.

The private ownership was a problem but, as the hall was used for a number of BBC broadcasts including the Proms, it seemed to be in the public interest to provide public money to help pay for any improvement which resulted in acoustic benefits to the public.

Of course we sent a sample to the Government Building Research people and they came back with a result which said that the saucers would reduce the reflection by 3dB – a result not understood by any of the big cheeses. But the comment from the Director sealed the project when he said he wished he had come up with this solution, making his admiration for that young acoustician very clear.

So the flying saucers were hung and the measurements showed that there was a definite improvement in the reverberation frequency response but curiously there was an increase in the low frequency reverberation time – an improvement very desirable for Stokovsky. It turned out that this improvement was due to work which had been done on the floor of the hall for boxing matches. But Stokovsky would be pleased anyway. In fact, he said at the time “The echo – which is different from the reverberation period – is much less intense than it used to be, and the reverberation period is definitely shorter but I think there is more that could be done.”

I don’t think musicians ever really trust scientists’ tests on halls. So the hall had to tested by a real orchestra. I remember very clearly sitting with that heroic acoustician listening to the LSO playing the Bruckner Eighth and saying, “They’re playing this just for us!!!”We were the only people in that huge old hall.

Four years later, Stokovsky gave his last concert in the Albert Hall.