what cause the "bees in a can" or "throathy roar" sound? why?

TIA

 

it can be lots of things - Cat back exhaust, Y pipe -
o bye the way - intake can create a roar too...

because the after market stuff is less restrictive it flows the exhaust out at a faster rate so it sounds louder , and the maxima doesnt have the honduh sound because it has more displacement than the honduh 4 banga's so it cranks out more
exhaust and junk like that......

intake makes noise cus it takes in more air at a rate of which the engine regulates ..... ( guys dont get on my *** about being non specific)

 

i believe the buzzing noise is caused by the flex piping in the down pipe. i believe throaty sound may be from larger diameter exhaust piping.