The V 28 is concepted as a straight waveguide horn with a vented transducer motor. The recommended active x-over frequency is 100 - 160 Hz, 18dB/oct. Butterworth. The 18" EVX 180A OEM loudspeaker chassis are reliably protected against critical power levels and short thermal overload by thermo switches and quadruple halogen lamp protection. The V 28 cabinet is made of 18 mm birch plywood. All corner joints and braces are grooved and glued in order to reduce cabinet resonances to a minimum. The cabinet surface is finished in extremely resistant structure black laquer. The connector panel uses two 4-pole Speakon connectors (Input/Output) for safe connection and easy chaining to the next loudspeaker. A powder-coated 2mm steel grid protects the cabinet front safely. 8 rubber feet can be fastened at the bottom or the sides and allow safe and stable stacking of the loudspeaker cabinets. The handle trays on the sides and the casters guarantee an easy and safe transport.