i have the cd rb10. it was only like 25 or 30 bucks. i get excellent sound out of mine. how much did it cost to make? check your wiring. maybe one of your rcas is loose. it happened to me once. it was loose highs worked and subs didnt. i tightened up the rca and pushed it all the way in and BAM subs came back on. BTW if it isnt a wiring problem just buy a used rb10. ull save urself a headache.