"to active for stuff above the bass”
Ii an active system, it is usually only the bass driver section that has significant impedance variations. So for example, use a voltage amp to drive the bass, and current amps to drive midrange & tweeter (or midTweeter in WAWs)
"variable transimpedance amplifier"
An amplifier with a dial that allows changing the output impedance from near zero to near infinity. A voltage amp at one end of the knob, a current amp at the other end and everything in-between.