Abstract: An apparatus for providing selectable multimodal vibration in a vibratory screen assembly to filter a bulk material of varying sizes. The vibratory screen assembly includes screen deck having a rigid portion and a flexible portion. The rigid portion formed by side plates, deck ends, and stability members. The flexible portion mounts within the rigid portion and includes flexible girders and support members. The support members are attached to the flexible girders and support a screen medium fixed to the rigid portion and covering the screen deck. The flexible girders include a tensioner and are held at varying tension levels to impact the vibratory frequencies of the screen deck at various locations. The vibratory screen assembly also includes a vibration-generator to provide vibration to the assembly. When vibrated, any bulk material on the screen deck experiences a range of linear and non-linear vibrational frequencies, increasing the effectiveness of filtration.