i need help building a ported box for two alpine type r.i have the in one already but i think the box is two small anmd tuned low because it doesnt hit as hard.ive seen other alpine type r in a bigger box and sound great,so so decided to build one but i dont how to start and i want to tune thebox from 35hz to 42hz.and i dont even know how to tune them.please any help with diagrams would really help thank u.