I spliced some speaker wire together 6 months back and now seem to be getting "extra" noise from the speakers. Could it possibly be the speaker wiring???
If the popping sound is coming from the woofer most often that is the voice coil former hitting the back plate. This is usually caused by overdriving the woofer. It can also be caused by a defective spider or other suspension component. Are you sure the sound isn't originating at the amp? Does it correspond with an appliance turning on (refrigerator)? If your splice was done correctly it's doubtful a spliced cable would cause a popping noise unless there is intermittent shorting of exposed wire.