DIY isobaric bandpass

Scored a pair of 400-Watt (RMS) 8" subwoofers for $52 USD to try Dual-Sub Isobaric Bandpass config in TSLA factory enclosure, mount, & location where each subwoofer features dual 4-ohm voicecoils that i connected in parallel to halve impedance down to 2 ohms; multiplied by 2 for same parallel wiring of voicecoils on other woofer = total of 4 ohms of resistance presented to the amplifier, thus preserving intact its original thermal efficiency (which was designed for a single, dual-voicecoil 8" subwoofer but thx to the isobaric config, i'm running 2 subwoofers w/o disturbing any of the factory setup..).

Although i had to connect the subwoofers with inverse polarity from each other so that one pulls as the other pushes to compound/bounce off of one another & thus naturally amplify the acoustic effects w/o any addt'l wattage or enclosure volume.