LFE (Low Frequency Effects)
Definition
A dedicated audio channel in surround and immersive audio formats designed specifically for low-frequency content below approximately 120 Hz. The ".1" in formats such as 5.1, 7.1, and 9.1.6 refers to this channel, which is routed to the subwoofer.
In Simple Terms
The dedicated bass channel in surround and Atmos setups — the ".1" in 5.1 or 7.1. It's what makes explosions shake your seat in the cinema and bass drops hit your chest at home.
In Practice
The deep rumble of an explosion in a film mix is placed in the LFE channel, creating physical impact through the subwoofer while the full-range speakers handle the mid and high-frequency content of the same event.
Common Confusion
LFE is not "the bass channel" — it is a dedicated effects channel for content below ~120 Hz that the engineer chooses to send there. Regular instrument bass (kick, bass guitar, synth bass) belongs in the full-range channels of the bed, where it gets reproduced by both subwoofer (via bass management) and main speakers. Routing all bass to LFE breaks bass management and produces a hollow mix.
Dolby Atmos Context
In Dolby Atmos, the LFE channel is part of the bed structure. It is a dedicated channel, not automatically generated from bass content — engineers must explicitly route low-frequency material to it.
Sources & Verification
- ITU-R BS.775-3 — Multichannel stereophonic sound systemInternational Telecommunication Union, 2012
- Holman, T. — 5.1 Surround Sound: Up and Running (2nd ed.)Focal Press, 2008
- Dolby Atmos Music Renderer Guide — Bass management and LFEDolby Laboratories
Last verified: 2026-05-05