Tips on using the LFE Channel in 5.1
The LFE is a channel and is not the same as the subwoofer. It’s actually a 120Hz bandwidth limited channel (80Hz for DTS) that has an additional 10 dB of electrical headroom above the 5 main channels. It was created as part of the film version of Dolby Digital to enhance low frequency sound effects, such as large explosions and other LF content which exceeded the headroom of the main channel. Hence the name LFE: Low Frequency Effects and not low frequency bass channel. So, unless you are recording Tchaikovsky’s 1812 Overture with REAL cannons, it doesn’t need to be used in most music applications, but can be useful in film and multimedia applications.
An important note about the LFE channel: Never put anything critical to the mix exclusively in the LFE channel. This is because when a Dolby Digital decoder folds down a 5.1 source, it drops the LFE channel completely (poof!).