Compel are a Doom/Sludge Metal band from Summerville, South Carolina. On their Facebook page they label their sound as 'Swamp Doom.' Their self-titled EP is available for free download.
This self titled EP is everything you'd imagine a Doom/Sludge EP to sound like. Long, slow and beautiful (or terrible, depending on your tolerance and/or taste for such things). If you don't know what Doom or Sludge sounds like, imagine taking a Black Sabbath instrumental, slowing it to a crawl, making it heavier and adding on tons of reverb. That is how I would describe the Compel sound. It is one long and heavy head jam from the time you press play until the last note echos and bounces around in your skull.
But because I'm not very good at this stuff, here are some other reviews of the EP for you: