The EMS-51 is completely passive, yet outperforms many bi-amplified or DSP-processed designs. The enclosure contains a 5” (127mm) LF drive unit, linked via the internal passive crossover network to a 1.1” (28mm) diaphragm HF soft dome drive unit which produces a 75° conical dispersion pattern. Unusually for a loudspeaker of this size, it is an infinite baffle design which gives a smoother LF rolloff and a much more robust LF performance than would be expected from an enclosure of this size.

The robust enclosure is constructed from premium multi-laminate Birch plywood and is finished in impact resistant textured paint. Two NL4 connections are provided on the rear for input and enclosure link. The front of the loudspeaker is protected by a rigid steel grille. Various threaded fixings are provided in the enclosure for the included rigging hardware.