Re: Derek Roddy
yes the "blast beat" or simply "blast" is something typical for fast death-or black metal.
there are many variations of it but it is mainly like lambo said, the bass drum is played half speed of your hands, your left hand is playing on the snare and your right hand usually on the ride cymbal.(usually hand to hand)
but what do you exactly mean by doubles? i am training my left hand at the moment mainly with multiple bounce rolls with metronome ,of course, by slowly increasing the speed.