Bass management

The fundamental principle of bass management (also called LFE crossover) in surround sound replay systems is that bass content in the incoming signal, irrespective of channel, should be directed only to loudspeakers capable of reproducing it, whether the latter are the main system loudspeakers or one or more subwoofers.

However, when there is no subwoofer, the bass manager directs the LFE channel to the main speakers.

[5][6] As shown in the bass management block diagram, a 5.1-channel audio system consists of five discrete, full-range main channels (front left, center, front right, surround left, and surround right), plus a band-limited low-frequency effects (LFE) channel for added bass (this corresponds to the .1).

In such a system, the use of bass management allows the redirection of low-frequency signals from any of the five main speakers to the subwoofer (SW).

The LFE channel for movies has a frequency range extending to 120 Hz, and some AV receivers apply a 120-Hz low-pass filter during playback, and this frequency is independent of the settings of the low-pass and high-pass filters that are applied to the main speakers.