The Bassmonsters were founded in 2009 by Claus Freudenstein to support the Band „Deep Purple“ at the „Great Wide Open“ Concert. To have a good name that fits to this event he choose the name „Bassmonsters“ for his ensemble that had 12 players in that time. After that the Bassmonsters went on developing their arrangements and adapted their playing technics to their new style. In 2012 they recorded their first CD „Classic meets Rock“ which is the first recording in history featuring 4 double basses playing rock classics in an electrified string quartet. And in the april 2014 issue of the „strad magazine“ the CD got a great review and the CD became known worldwide. Since this time the Bassmonsters played many successfull concerts in amazing concert halls and festivals all over the place. The most important concert in the career of the Bassmonsters was their show at the 2015 ́s ISB convention in Fort Collins/Collorado. After this concert their video recording of the Gun ́s Roses song „Sweet Child o ́mine“ become one of the 10 most watched videos on Americas most frequented Bass website „notreble.com Between 2015 and 2019 Claus Freudenstein invited eleven top contrabassists to collaborate on an unprecedented musical project. The result is the album UNIO. An amazingly exciting auditory sensation that appeals to both young and old, in this ensemble the double bass goes "Rock 'n Roll," from Germany around the world!