There are 4 projects called "Placid".
1) - A Industrial Project from the Spanish Members of Proyecto Mirage:
http://www.discogs.com/artist/Placid
2) - A Digital Hardcore / Industrial Rock project.
3) - A Techno Project:
http://www.jamendo.com/en/artist/placid
4) A DJ from Bristol specializing in early Chicago House.
http://www.acid-house.net