This study investigates the sound insulation capabilities of two electromagnetic induction membranes controlled by shunt circuits in the duct sound field. The real and imaginary parts of the diaphragm acoustic impedance can be precisely decoupled and regulated through the operational amplifiers and adjustable resistors in the shunt circuits. The parameter indicators ΓH(B2l2/(2MmRδ2)) and ΓL(B2l2Cm/(2Rδ2)) are also presented to evaluate the adjustable performance of the diaphragm and the side sound insulation performance. Finally, the performance of a duct sound insulation system composed of two electromagnetic units was demonstrated through theory and experiments. The maximum sound insulation level was 17.4 dB with a pair of units.