Troffer-style lighting fixtures are disclosed having troffer housing with reflective regions, and respective light emitting diode (LED) arrays mounted in the reflective regions. The LED arrays are arranged to emit out of said troffer housing to illuminate a room below the troffer fixture. The LED arrays can be driven by an elevated drive signal to produce a relatively high luminous flux. The light fixtures according to the present invention can have lenses and diffusers over the arrays arranged to mix and disperse light from the light source to reduce or eliminate hot spots and to reduce or eliminate the appearance of the different LED colors. A plurality of first diffusers are included, each of which is over a respective one of the LED arrays. A second diffuser is included over the first diffusers, with the LED light passing through the first and second diffusers prior to emitting from the lighting fixture. The first and second diffusers can have shapes, surfaces or materials to disperse and/or mix the LED light as it emits from said fixtures.