Reply to Broken Studio Monitor. Help!!!!!!!!!!!!!!!

Right, so I was having a mix earlier,at low volume when all of a sudden the bass from one of my monitors started distorting. I turned it off straight away but now there's no low end whatsoever coming from it and the volume is very quiet. Any idea what could be wrong? They're Mackie MR8 active monitors. Does it sound like a broken driver or amp? Any help would be greatly appreciated. Cheers