source material could just be recorded in error. Also speaker placement and the acoustics of the listening environment can effect the phase. No matter what or where the cause is located, the solution is an easy one.
PHASE CORRECTING PROCEDURE
Disconnect all but one Bazooka® from your system. Be sure that any loose wire connections are insulated to avoid the chance of short-circuiting any of the electronic equipment. Listen to the system and take note of the level of the Bass Response. Connect the next Bazooka® and compare the level of the combined output to that of the single unit. If the Bass Response increases, the Phasing is correct and you can repeat this process on the next Bazooka. If the level of the Bass Response drops, the Phasing is incorrect and you should reverse the speaker connections to this Bazooka® and compare again. In short to INCREASE IS GOOD, to DECREASE IS BAD! Using this method, any number of Bazooka® subwoofers can be kept in absolute phase.
PRACTICE SAFE LISTENING
Continuous exposure to high volumes of sound may cause permanent hearing loss. High-powered auto sound systems are capable of producing sounds well over 130 dB. Even short periods of play at high volume levels can impair your ability to hear necessary traffic sounds and may constitute a hazard. Please use common sense and practice SAFE LISTENING!