I just installed this headunit in my 2005.5 jetta, and I cannot figure out how to adjust the bass level. I can get to the subwoofer settings, but there is no actual bass level adjustment. Before this headunit I had the stock with a line out converter and so my signal was amped. Now that I put in this headunit my bass feels alot lighter, but I like heavy where I can feel it. I went into the store I bought it and he told me to put it into custom EQ to change the bass, but I did this and still no success. Does anyone know what to do? Is there a certain frequency I need to set so it hits harder?