I can't figure out how to make a good bass line or get a good quality bass sound. If there is a tutorial or can someone help me please. I have Reason 2.5 and a midi keyboard to work with reason. Also anyone know or can get me some good hip hop refills of sounds, drum, bass, etc...

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Put your little freestyles out/
Don't know'em but your boys get'em/
Ask the kid on the corner I mop the floor wit'em "SWEEP!!!"/
A nigga talk bout me he need the lord wit'em/
or guardian angel on tour wit'em/
I turn your friends against ya I make u wish u wasn't/
I'm part of your family more like a distant cousin/
http://www.soundclick.com/bands/4/acnc_music.htm