As a special case, stereo processing of any number of sources can be accomplished using two delay lines, corresponding to left and right stereo channels. The stereo mix may contain a panned mixture of any number sources, each with its own stereo placement, path filtering, and Doppler shift. The two stereo outputs may correspond to ``left and right ears,'' or, more generally, to left- and right-channel microphones in a studio recording set-up.