A loudspeaker unit comprises a loudspeaker box, a first loudspeaker attached to a front panel of the loudspeaker box, and a second loudspeaker having the same diameter as that of the first loudspeaker and attached to an upper panel of the loudspeaker box. The first loudspeaker is driven in a positive polarity and the second loudspeaker is driven in a negative polarity. Driving voltages E1 and -E2 respectively for driving the first and the second loudspeaker are optional voltages meeting E2/E1