Emu XL-7 & MP-7 User's Group

I am in need of some help - I am trying to get my sub to really hum 
with some really intense bass - not quick and thumpy bass but loud 
sustained humming warm loving bass - I have tried to turn up the 
duration on the notes individually but the paremeters don't go high 
enough - for instance I want to get one note to play for two or three 
whole bars at least alone with almost the same velocity the whole time -
 also when I try increasing the gain it messes up the sound and muffles 
it - I want to get the bass as loud as possible and be able to control  
how long the bass plays ext... can someone give me some advice on all 
the parameters I need to adjust in order to get what I am talking 
about -