A methodology to control transient noise transmission is presented. Th
e applicability of H-2 optimal control in this setting is investigated
and it is shown why this approach is particularly useful in the trans
ient case. A design example is included that demonstrates how an activ
e controller can be used to reduce the noise transmitted into a three-
dimensional cavity through a flexible wall. It is concluded that this
approach does in fact achieve the objectives of transient control with
a stable, optimal controller incorporating a feedforward and a feedba
ck component. (C) 1997 Elsevier Science Ltd.