A signal processing system for controlling a lower frequency acoustic range of an acoustic output of a loudspeaker system. The system includes an input to receive at least a first channel audio signal, corresponding to the acoustic output of at least one loudspeaker with at least one electro-acoustic transducer with a vibratile diaphragm. The signal processing system includes at least one transpositional gain controller processor for transposition of at least a portion of the amplitude of at least one band of frequencies in a lower frequency audio signal range of the audio signal, to an increased gain in at least one transpositional target frequency in the lower frequency audio signal range. The transpositional gain controller processor includes at least one of at least one, static or dynamic, transpositional gain controller. The system may include at least one additional signal processor, supporting preservation of a perceived fidelity of the acoustic output.