As a practicable means for extending the low‐frequency response of small loudspeaker systems, schemes employing stabilized passive negative springs have been investigated. Experimental loudspeaker systems have been constructed and are described. A typical negative‐spring loudspeaker system, consisting of a 4.3‐in.‐diam diaphragm in a sealed enclosure of 0.105 ft3provides a piston displacement of 0.200 in. peak‐to‐peak at 65 Hz, when driven by an input power of 2.3 W into a nominal voice‐coil impedance of 11 Ω.