Abstract: A woofer module is provided for use in a television set, which comprises a hollow enclosure and a woofer accommodated within the enclosure for reproducing a sound of low audible frequency band. The enclosure has a first sound wave passageway extending from a front side of the woofer toward a first open end and a second sound wave passageway extending from rear side of the woofer toward a second open end. The second passageway is divided into an upstream region, a middle expansion region and a downstream region. The upstream region is contiguous to the rear side of the woofer and has a cross-sectional area smaller than that of the expansion region so that an equivalent air mass can be applied to the woofer.