We've all seen the dithering options in Logic's Bounce to Disc window. And likely select one of them out of habit before pressing the bounce button. But what do these different algorithms do? What do they sound like? 

Dithering is adding some form of noise shaping when reducing a file from 24 bit to 16 bit. When we get into really low-level signals, like reverb tails, it becomes difficult for digital algorithms to know whether the necessary bits should be turned on or off. The process of rounding off low-level signals to fewer bits creates "quantization noise." 

Dithering adds a small amount of very controlled noise to the original signal, so the bits can be made to switch on or off. The noise used is often "shaped" to sound as smooth as possible. Logic provides four different types of shaping used to dither an audio file during bounce down. 

In this video, I'll take the low-level fade of a reverb tail generated by Chromaverb and bounce it down four times, each using a different type of dithering. Adding Logic's Gain plug-in on playback raises the level sufficiently to hear the effects of the various noise shaping processes on the bounded audio files. 

Which of the various choices sounds the smoothest to you?