Dither is a very small amount of noise that is applied to digital audio as it is quantized to a lower resolution. This actually reduces the amount of distortion introduced by the quantization, and creates a more pleasing sound for material with a wide dynamic range.

Digital Performer 2.5 and later include the MasterWorks Limiter, as well as many new mastering plug-ins. The MW Limiter can use dither when converting files from 24 bit down to 16 bit resolution. Quantizing is used to reduce bit depth, and dithering is used to "soften" the quantizing.