A type of mixer that allows any input to be routed to any output. This is accomplished through a relatively elaborate bussing system whereby each output is driven by n number of level controls (where n in this case is equal to the number of input channels). With a modern matrix-mixer, not only can you assign any input to any output but you may add EQ, compression, etc. This is basically how a typical stage monitor mixer is designed. Though it is increasingly common to find matrix features on house mixers (especially those used in theater environments) to supply alternate (optimized) mixes to different areas of the venue. Very elaborate models exist with as many as 60-channels in and 24 or more output channels (and are as big as a Volkswagen).