How does the subwoofer +10 dB LFE level function work?
The LFE channel is usually recorded 10 dB lower than the main channels so that there is 10 dB of extra level (headroom) available. Most processors automatically add 10 dB to the LFE channel to restore the level in the LFE channel. The subwoofer sensitivity must be the same as the sensitivity in the main monitors. Then, the LFE channel level selection is set to ‘0 dB’ gain setting in the subwoofer.
The monitors should have a flat frequency response for accurate monitoring. This is achieved by calibrating the main channel frequency responses as described in the FAQ:
Q: How do I align the levels of a 5.1 system by using pink noise as a test signal?
A: The block diagram below shows the whole production chain.
Some medium format mixing consoles and many smaller consoles do not have the facility to apply the +10 dB gain to the LFE. To overcome this limitation Genelec subwoofers provide a +10 dB LFE gain selection.