The LS4 uses four identical push-pull modules, each comprising a central HF section operating above 750Hz flanked by midrange sections covering the 80Hz range. The backwave is absorbed within the enclosure, but the enormous radiating area still gives a sensitvity of 100dB/2.83V/m. (Impedance is 4 ohms.) Though the LS4 is fastened to the wall behind it, the weight is supported by a single spiked foot.
The LS4 is where architectural audio becomes aspirational audio.