Matthew, Sounds very much like the MIDI Matrix 2 I built years ago: http://www.milton.arachsys.com/nj71/index.php?menu=1&submenu=0 Except I used a CPLD to house the switching muxes. The trickiest part to make was the front panel, but it was worth it in the end. Cheers, Neil -- http://www.njohnson.co.uk