Description The KF911F is a dedicated high frequency downfill module engineered for use with Phase Point Source Technology™ digital signal processing in the creation of PPST™ arrays. It provides coverage from -15° to -45° below the horizontal axis with flat frequency response. Usable frequency response is provided to -60° below the horizontal axis. The system comprises two cells of a specially designed 2 in exit/3 in voice coil compression driver loaded on a 30° horizontal coverage SimplePhase™ horn. Sophisticated horn-loading technology allows the KF911F to provide focused downfill coverage without "breaking" the bottom of the enclosure. The lower cell\'s high frequency compression driver employs a near instantaneous reflection off the top of the cell to gain additional "bend" to reach 60° below horizontal. Because the enclosure\'s bottom is sealed the downfill element can be placed at any location in the array -- not only on the bottom row. SimplePhase™ horns were specially designed to facilitate the PPST™ process. Horizontal coverage is an idealized 30° over the entire operating bandwidth. Unlike Virtual Array Technology\'s complex horn flares designed for control of individual drivers the simple lines of the SimplePhase™ horns produce phase-coherent summation with other drivers within the module.

Applications The KF911F PPST™ downfill HF module is engineered for use only in KF900 Series arrays implementing PPST™ digital signal processing. It is not intended for stand alone use of any kind. With appropriate PPST processing the KF911F provides vertical HF coverage from -15° to -45° below the array with flat frequency response and provides usable response to -60°. It ideally complements the KF910F long throw module to provide complete HF coverage and should be placed directly below the KF910F. Because the enclosure\'s bottom is sealed the downfill element can be placed at any location in the array -- not only on the bottom row. This is particularly important in portable applications in which the KF910F long throw elements must be raised to the top of the array. In such a case the KF911F downfill elements can also be raised. In stadium and arena applications where the highest seats are above the array an inverted KF911F can provide "up-fill" coverage. In such a case it is does not necessarily need to be positioned adjacent to the KF910F long throw element.