FabFilter Pro‑L 2 Help
FabFilter Pro-L 2 support all important surround formats, up to 7.1.2 Dolby Atmos. When you add Pro-L 2 to a surround channel, the interface automatically adapts itself for the used multi-channel format. The output level meter will show all channels, with appropriate labels to identify them. In addition, the Channel Linking section in the Advanced controls panel, will have additional surround functionality.
When using Pro-L 2 on a surround channel, the Channel Linking section in the Advanced controls will offer a different, more extensive functionality: the Transients and Release knobs have an extra range (from "100% Stereo" to "100% All", and additional C and LFE buttons are available.
In the first half of the range (from "0% Stereo" to "100% Stereo"), the Transient and Release link knobs work the same as in the stereo version of the plug-in: it controls the amount of linking between L and R channels (e.g. L/R, Ls/Rs, Lc/Rc or Lts/Rts). However, every stereo pair's linking is still independent of the other stereo pairs.
In the second half of the range (from "100% Stereo, 0% All" to "100% Stereo, 100% All"), all channels will interpolate to full all-channel linking, where every channel triggers on the same signal: the maximum of all channels.
With the C button enabled, the center channels (C, Cs) will be included in the linking of their associated L/R stereo pair, i.e. C is linked to L/R and Cs to Ls/Rs. When leaving it disabled (which it is by default), the center channels will always stay unlinked and operate fully independent from all other channels.
With the LFE button enabled, the LFE channel will be included in the all-channel linking in the second half of the range. When leaving it disabled (default), the LFE channel will always stay unlinked and operate fully independent from other channels.