Optimisation of an active noise control system for reducing the sound transmission through a double-glazing window

The implementation of an active noise control system in the cavity of a double-glazing window has been investigated. In a preliminary theoretical analysis the spatial distribution of both the control loudspeakers and the error microphones of the control system has been optimised with respect to the reduction of the acoustic potential energy in the cavity between the two glass plates using a simple genetic algorithm. The comparison of the reductions achieved by the optimised central system, with the reductions achievable with an idealised control system, which assumes a perfect knowledge of the dynamic characteristics of the double-glazing window, permits an evaluation of the performance of the optimisation process. It appears from the experimental analysis that the optimised control configuration yields far better increases in the sound transmission loss than a randomly chosen configuration. The obtained reductions in the transmitted sound power illustrate the potentials of active noise control for improving the sound insulation characteristics of double-glazing windows.