The present disclosure includes systems and methods for solving speckle problems by exciting the screen with a more complex vibration spectrum. A range of frequencies provides, in effect, a collection of overlapping patterns of high and low displacement, so that all regions of the screen have enough motion to reduce visible speckle. As previously discussed acceptable speckle may be approximately 15% contrast or less, preferably approximately 5% contrast or less at approximately 15 feet from the screen.