R&D Report 1963-49 : Noise and vibration levels on the South Bank site of the proposed opera house and National Theatre. C.L.S. Gilford. Measurements of airborne noise and ground vibration on the South Bank of the Thames between County Hall and Hungerford Bridge show that the roofs of the proposed National Theatre and Opera House should give a mean sound reduction of 69 dB with a slope not exceeding 7 dB per octave. Protection of the National Theatre from vibration will present considerable problems since it will be situated immediately above the Bakerloo tunnel; if possible the theatre should be moved to a position further from Hungerford Bridge.