The present invention is to provide a speaker cabinet comprising a hollow case in which a top and a bottom thereof both are wavily tapered from a pair of opposite edges of a front opening to a rear thereof. By utilizing the wavy, rearward taper design of the top and the bottom, a ratio of an area of the opening to an area of the rear is increased. Thus, air inside the case will be compressed rearward when a diaphragm of a woofer vibrates. Next, the compressed air will quickly flow toward the rear along the wavy, rearward taper inner surfaces of the top and the bottom. As a result, air dynamic at the rear is higher and stronger low-frequency resonance of the cabinet can be generated.