Series - One Speaker (Dual 2 ohm voice coils)
One dual 2 ohm voice coil woofer with voice coils
in series results in a 4 ohm load to the amplifier
Parallel - One Speaker (Dual 2 ohm voice coils)
One dual 2 ohm voice coil woofer with voice coils
in parallel results in a 1 ohm load to
the amplifier
Parallel - One Speaker (Dual 4 ohm voice coils)
One dual 4 ohm voice coil woofer with voice coils
in parallel results in a 2 ohm load to
the amplifier
Series - One Speaker (Dual 4 ohm voice coils)
One dual 4 ohm voice coil woofer with voice coils
in series results in a 8 ohm load to the amplifier