AP 6.5 Ω2 woofer has been developed with 2Ω nominal impedance with the purpose of exploiting all the power made available by the AP8.9 bit amplifier capable of 65W into a 2Ω load. To maximize the woofer efficiency achieving 95 dB, a 25 mm diameter 10 mm winding height coil, so a more lightweight coil, has been employed, at the same tim...