FabFilter Pro-R online help

Table of contents

Predelay, input and output options

The Predelay button at the bottom center of the interface opens a panel with the Predelay settings:

FabFilter Pro-R Predelay

  • The Predelay knob controls the initial delay between the original sound and the start of the reverb. Adding a bit of predelay increases the separation between the original sound and its reverb tail. For example, moving the reverb tail away from a vocal can highly improve the clarity and transparency of a mix. Predelay also contributes to the sense of space. Higher predelay settings tend to increase the perceived room size. Increasing predelay instead of the overall decay time can work well in achieving a less intrusive, more natural reverb that sits better in a mix.
  • The Predelay Sync button lets you easily synchronize the predelay time to host tempo. By default, synching is off and the normal delay time is used. Other options are: Quarter Note, 8th Note, 16th Note and 32th Note.
  • The Predelay Offset knob replaces the normal Predelay time knob as soon as Predelay Sync is enabled. The offset knob lets you scale the predelay from 50% to 200% of the synchronized time. This way, you can easily achieve dotted (150%) or triplet (67%) effects.

At the right bottom of the interface, you'll find the bypass, input level and output level controls, all accessed via a single output button. As soon as you hover the mouse above the output button, a panel will pop up, giving you access to the following settings:

FabFilter Pro-R Output options

  • The Input Level/Pan knob at the left adjusts the level and L/R panning of the input signal before any processing is applied.
  • The Output Level/Pan knob at the right adjusts the level and L/R panning of the final output signal.
  • The Global Bypass toggle button bypasses the entire plugin. While most hosts already provide the ability to bypass plug-ins, our internal global bypass feature is guaranteed to correctly compensate the latency of the plug-in and it also applies soft bypassing to avoid clicks. While the plug-in is bypassed, the spectrum analyzer stops and a red light glows in the bypass button itself. The top of the output button in the bottom bar is also highlighted in red.


  • You can directly adjust the predelay, input- or output gain by clicking and dragging the button text vertically. You can use your mouse wheel while hovering over the button text or double-click it to directly enter a value using the keyboard.
  • If desired, you can make the predelay or output options panel 'sticky' by clicking the predelay or output button once. Click it again to hide the panel.
  • By holding down the Alt key (Shift key in Pro Tools) while dragging, input and output level can be adjusted simultaneously in the opposite direction.
  • The output level controls the overall output of the plug-in including the dry signal that is mixed in. The input level only controls the level of the signal going into the reverb engine, without adjusting the dry level. You can therefore use the input level to adjust the level of the "wet" reverb signal relative to the dry signal, which influences the behavior of the Mix knob.
  • Panning the input is different from panning the output, because the reverb will spread the signal again. You can use this to get the effect that the input signal is originating from one side of the room.
  • The spectrum analyzer shows the audio signals after applying the input level, but before applying the dry/wet mix and output level.

Next: MIDI Learn

See Also
Using FabFilter Pro-R

Table of contents