Oberheim Matrix synthesizers were a product line of subtractive analog synthesizers from Oberheim featuring a system of modulation which Oberheim called "Matrix Modulation" as a method of selecting and routing elements that dynamically shape various aspects of the sounds it produces. Matrix synthesizers continue to be popular due to their characteristic late-1980s analog sound and leading patching and filter capabilities.
These five products fall into two groups. The Xpander is a six-voice rack-mount synthesizer with voltage-controlled oscillators and very flexible voltage-controlled filters. The Matrix-12 is in effect two Xpanders plus a keyboard. The second group consists of the Matrix-6 synthesizer, with DCOs, and much more standard filter capability. It had two rack-mount variants, the Matrix-6R (Matrix-6 without keyboard) and the Matrix-1000 (low cost preset version with extended memory).