The world loves the sound of dubstep, and that's due in no small part to Martin Clark's influential writings. His detailed documentation of grime and dubstep has seen the Croydon sound travel around the world, and the kids are ready for deep bass and sparse beats. Beginning with a sample from some unknown Eastern cassette tape, we are instantly in dubstep nirvana, one foot firmly in China and one foot in a muddy puddle on the estates of South London.A1. Focus