I am not sure what to set my hipass and lowpass frequency on my alpine head unit cda-7873. I have 4 door speakers boston rally 5x7 with apline flex-4 amp. And then I have a JL audio sub in my center console with a JL audio 250w amp. What should I set my crossover to.
I'd try 120Hz 12dB slope for the 5x7s, and 80Hz 18dB slope for the sub as a starting point. the 1 octave gap will be filled in by the roll off of the two slopes, so you won't have anything missing, and 120Hz should keep those small 5x7s from bottoming out on you.