To provide a method and apparatus that take into account at least some of the following issues as well as possibly other issues: time and effort are required for installation, additional space is required, the system is expensive, weight is increased, or the amount of noise reduction achieved may not be as great as desired.

A composite panel has a first face sheet 404, a second face sheet 406, and a core 408 located between the first face sheet and the second face sheet. Arbitrary number of structures 410 is associated with the first face sheet. The arbitrary number of structures has a mass with a configuration to reduce a speed of waves propagating in the composite panel such that noise radiated from the composite panel is reduced.