I'm not sure how your system is designed, but the best placement for most installs is:1) Sub-mid bass in kicks on access to the listener if possible (some people say it doesn't matter, I say BS). Usually cross at 500hz or below, usually ~325hz. I have my 8's LPF at 80 or 500 depending on type of music.
2) Mid-full range pointed straight across to the other door panel, off axis (less beaming). Xover point usually blends with mid-bass and cuts off around 3Khz, 6 or 12db slope.
3) Tweeter in a pillar or front dash. Some people prefer off axis and reflecting sound off panels to deaden harsh sound. Depends on personal preference.
