Sound system culture is very much alive in Belgium or Beljam as it’s called in reggae/dub circles. On Saturday at Mekitburn festival no less then four full sound systems were present, and three of them Belgian: Satta Sound, Gamma Sound and Skyfire.
There’s a whole lotta sound systems in Belgium. Not all of them have build their own full sounds, but a lot have and there are some really impressive sounds there: http://www.reggae.be/en/community/soundsystems
Review in Dutch of reggae and dub at Mekitburn: http://www.reggae.be/nl/magazine/event_reports/Heartical_fire__Mekitburn_Festival