KEF Q900W Floorstanding Loudspeaker - American Walnut (Single) The Q900 features a specially-voiced 8 inch aluminum Uni-Q driver, with a 1 inch vented aluminium dome tweeter at its acoustic center. This driver provides both high and mid frequencies from one source, much like the human voice. Below the Uni-Q driver array are three stacked 8 inch bass drivers working in tandem to quickly and efficiently produce a range of low frequencies. The Q900's odf-axis dispersion is unrivaled, meaning everyone in the room enjoys the same exceptionally realistic sonic imaging wherever they sit. The Q900 sits on an aluminum plate supported by four steel 'plinth' spikes with locking knobs for easy height adjustment. The plinths also serve to ground the Q900, resulting in a rigid connection that eliminates any rocking resonances.