I have an alpine cda-9855 and i has the option to use a 7 band graphic or a 5 band parametric.. what is the difference between the graphic and parametric??

http://stereos.about.com/cs/componentguide/a/equalizers.htm

Neither is better per say... it depends on what your personal comfort is with either type. I prefer graphic, but a lot of the time, I use the parametric eq to figure out which frequency is the problem & then use the graphic eq to dial it in.

I prefer to use a parametric to solve the frequency response issues that are intrinsic to the install, but the graphic to tune down the overexcited parts of the drivers.