purchased a 20 db line level booster, thinking i could increase signal or boost voltage to sub, at 50', as i feel it movig, yet no real audio, no change,it has a control for db gain, is this not even what i need?, i had read on here where a guy did this, claimed he was satisfied, cheap so i tryed, i have done so with small car cross. with bass boost, with a/c d/c converter, worked great, what else can i do,it's being fed from pre out from another sub. that works great, i'll figure something if someone else dosn't i guess, i could always buy more subs-nah