Wirelessly linking a portable audio device to an external audio system
permits the external audio system to generate audible signals that
enhance local playback of audio by the portable device. For example, the
portable device wirelessly transmits lower frequency components of an
audio signal to a subwoofer system for reproduction of bass frequencies
extending below the playback capability of the portable device. In this
manner, the external audio system provides bass enhancement for the
portable audio device. Wireless transmissions between the portable audio
device and the external audio system may be, but are not limited to,
optical or radio frequency (RF) transmissions. Where RF signaling is
used, the wireless link may be based on wireless network links, such as
those supported by Bluetooth and 802.11b standards, or based on, for
example, dedicated RF interfaces.