Methods and apparatuses for addressing open space noise are disclosed using both dynamic and static sound masking. In one example, an adaptive sound masking system and method portions undesired sound into time-blocks and estimates frequency spectrum and power level, and continuously generates masking noise with a matching or predetermined spectrum and loudness or power level to mask the undesired sound. In another example, a static sound masking system and method portions undesired sound into time-blocks and estimates frequency spectrum and power level, and generates a static noise-masking signal with a matching spectrum and power level to mask the undesired sound.