There are at least 6 artists under the name Multiplex. 1) Multiplex are Electronic Brothers Christian and Roland Dormon - They have releases on Toytronic, Senton, Humanshield and U-Cover records.
(www.myspace.com/multiplexmusic) a good selection of their tracks are up here on the last.fm playlist 2) San Diego synth pop duo formed in 2012 and uses various analog synthesizers and drum machines

Read more about Multiplex on Last.fm.