We have investigated new trapezoidal noise reducer for acoustic fins in St. Martins and carried out a bunch of tests on its acoustic performance. Some test results imply that the insertion loss of such design is higher than rectangular noise reducer having similar construction.

The tests were carried out on 27th March in a full anechoic chamber and utilising a series of loudspeakers to simulate traffic noise condition. The acoustic performance of the acoustic fins with this noise reducer is proven satisfactory and this is an effective outdoor noise mitigation measure.