Henry Wood Hall: The Creation of a Flexible Acoustic Using Airbeds

Henry Wood Hall is a former church in central London repurposed as an orchestral rehearsal space. Its success in this role since the 1970s is testament to its suitability for this purpose. However, the trustees of the hall wanted a more flexible use of the space and in March 2018 instructed the Acoustics Group to develop, test and install a solution which would create a balanced acoustic suited to smaller ensembles such as those used in Operatic productions. This would require the reduction of the natural reverberation boost that the hall provides at low frequencies. The solution should, for a modest budget, be flexible enough to be changed within the hour-long break between sessions. Laboratory tests were undertaken on inflated airbeds in the LSBU reverberation chamber to determine the low frequency absorption potential of these consumer goods. An airbed model was selected with the most promising performance and optimum positioning was determined. Room acoustic measurements were taken in the hall before and after the airbeds were installed, showing significant reduction in reverberation time in the lower frequency bands.