so i bought a set of skar tx 65c 2 way component speaker with passive crossover, and i have sundown audio sae 100.4 that will be powering them. My first question is what hz should i be using to find my max volume on head unit?..... and what HZ should i use to set my gain at? and i was told to use the same Hz for (HPF) on 4 channel and (LPF) on mono block amp. and i will be using a o scope to set all my gains. any help would be awesome thanks.