in an audio setup, you choose your a SVC or DVC depending on the amp you are pairing the sub too. always use both coils on a dvc, if you only use one it will only receive half the power to the sub and it throws off all teile-small parameters when matching the sub to the proper encloser.

if your audiobahn subs are matched right for your amp then try this...check your ground from your capacitor/amp to ensure it isnt loose at the frame where it is bolted to the chassis and the paint is removed to bare metal. also the ground wire should be 4 ga. or larger if your power wire is 4ga.

also use a meter to test each sub for its proper impedance to ensure they are not blown, causing the amp to overheat.