Low-Frequency Effects. The subwoofer channel signal in a 5.1 surround mix. The equivalent of the subwoofer designation for audio-for-video, where the low-frequency band between about 20 Hz-120Hz is matrixed or channeled for replay. In home audio systems, the subwoofer will frequently contain low frequency information from the main channels in addition to the original LFE track.
See also in-band gain.