SERIES & PARALLEL SPEAKER WIRING - HomeToys Jun 01, 2002The formular for Series Wiring is: Znet=Z1+Z2+Z3. PARALLEL SPEAKER WIRING: Parallel circuits are the simplest electrical circuit to wire. Adding Speakers in parallel decreases the overall resistance of the circuit Parallel Speaker Wiring combines all Speakers (+) positive Speaker leads together, and all (-) negative Speaker leads together. Speaker / Amplifier Wiring Guide - DIY Audio & Video When wired in series, these differences will cause distortion in the form of back EMF. You can however run both coils of a DVC (Dual Voice Coil) speaker in series. The cone movement for both coils will be identical, and will not cause distortion problems. This is the formula to calculate the impedance of speakers in series.