A low cost/high efficiency passive radiator module component includes: a ported cavity structure adapted for placement inside an acoustic enclosure with a port communicating out of the acoustic enclosure and one or more pairs of passive radiators symmetrically oriented and supported on opposing side walls of the ported cavity each having a predetermined or tuned mass distribution, stiff acoustic radiating diaphragm surfaces, and spaced apart inner and outer suspensions configured to suppress diaphragm wobble that induces each pair to symmetrically vibrate inertially responsive to variable sound pressure pulses originating from an active acoustic radiator within the acoustic enclosure. Different variable acoustic pressure pulses may be detected inside and outside the ported cavity; the constricting horn connecting to the ported cavity from outside may be tuned by horn loading to achieve a desired effect.