Multi-channel reproduction of spatial audio can be approached in several ways. Typically, several loudspeakers are placed in a listening space and a discrete signal is sent to each. Many loudspeaker configurations and signal capturing/generation techniques exist. Systems vary from the omni-prevalent two channel stereo to large Wave Field Synthesis loudspeaker arrays. Stereo and quadraphonic spatialization algorithms are typically based on amplitude panning, which has recently been extended using vector based techniques. Other approaches include Ambisonics, which employs spherical harmonics to decompose the sound field, and Wave Field Synthesis, which is based on the Huygens Principle of Wave Propagation. Respective systems can be critically assessed based on attributes such as spatial accuracy, complexity and practicality.