The improved bass and low-mid response we noted in our review falls in line with iFixit's confirmation that the new driver in each Pod is made with a paper speaker cone -- in contrast to the plastic used on the older model.
Tri-Amping - A technique commonly used in large-scale sound amplification for concerts, Tri-amping is the practice of connecting three audio amplifiers to a loudspeaker unit: one to power the bass driver (woofer), one to power the mid-range and the third to power the treble driver (tweeter).