possibly a massive noob question but i have no idea

ok, listening to music with fast double kicks and a heavy bass line over the top i notice my sub tends to end up making just a boooooooom sort of sound instead of actually playing the individual kick from the bass drum, now, is this the tuning of my sub, or would it be id need a sub if a faster efficiency rate? btw its only a soundstream, swex12 or something, nothing special.