A system provides white light having a selectable spectral characteristic (e.g. a selectable color temperature and intensity) using a combination of sources (e.g. LEDs) emitting light of four, five, or six different characteristics, for example, one or more white LEDs, and one or more LEDs of each of three primary colors plus cyan and royal blue. A microcontroller can maintain a desired spectral characteristic, e.g. for white light at a selected point on or within a desired range of the black body curve. Further, the microcontroller provides tunability of the spectral characteristic and intensity of the white luminaire. One channel driver drives the one or more first color LEDs (white in our example) as well as the one or more second color LEDs which are connected in series to the first channel driver. The other light sources are each driven by separate drivers on separate channels.