Abstract: A unit for use in coupling a pair of loudspeakers to an amplifier having two channels comprises a transformer having a first winding and a second winding, one end of a first winding having a first connection device for connecting the first winding in series with one of the loudspeakers, one end of the second winding having a second connection device for connecting the second winding in series with the other of the loudspeakers, the windings being electrically connected asymmetrically, and the other ends of the first and second windings having means for connecting the other ends to the negative supply line of the amplifier. This unit can be used advantageously in connecting the front speaker pair of a "surround-sound" or four speaker sound reproduction system. The remaining speaker pair is then connected in a conventional Hafler arrangement.