simple rule for parallel wiring i use. 2 4Ω speakers. divide the Ω into how many speakers you will wire. i have 2 D4 ohm subs. so thats 4 4 ohm coils. 4 divided into 4 = 1. 1 ohm final load. thats the simple stuff. it can get harder once you try series/ parallel on multiple subs or speakers.