FabFilter Pro-R offers seven intuitive main controls to control the behavior of the reverb algorithm:
Prominent at the center, the Space knob is obviously the most important control of Pro-R. It smartly and smoothly combines the room model and decay time of the reverb, ranging from a very small ambience space (200 ms) to a cathedral-like ten-second reverb. With this single control, you can choose from over a dozen carefully designed room models and seamlessly vary between them, without hearing clicks or unwanted artifacts. The decay time varies automatically to match the room model. The yellow time label in the Space knob shows the current reverb decay time (possibly affected by the Decay Rate setting). Tip: As a shortcut, you can directly click the room icons around the Space knob.
The Decay Rate control lets you adjust the reverb decay from 50% to 200% of the decay that corresponds to the current Space setting. This allows you to easily fine-tune a room model to have the decay that it needs in the mix. The yellow time label in the Space knob will always display the final reverb decay time, together with the original time and decay rate if not at 100%.
The Brightness knob adjusts the clarity and high/low frequency balance of the reverb. Lower Brightness values correspond to spaces with more high-frequency absorption. In real spaces, high frequencies are very easily absorbed, depending on the surface of walls and curtains or objects in the room. The average room or hall has a pretty dark reverb sound. Therefore, turning down the Brightness a bit often gives you a more natural and realistic sounding reverb.
The Character control brings life to the reverb sound in various ways. At 0%, the reverb is as transparent and predictable as possible. Turning the knob up to 50% gradually introduces some modulation and more pronounced early reflections together with subtle yet noticeable late echoes. From 50% and up, the reverb begins modulating more and more, up to a chorus-like effect at 100% which works well on vocals and synths.
The Distance knob controls the effect of moving closer to, or further away from the sound source in the modelled space. At 0%, the reverb sounds as if you are quite close to the sound source, with more pronounced and brighter early reflections. Increasing the Distance sounds like walking away from the sound source in the current space, resulting in a longer build-up and a more diffuse tail.
The Stereo Width knob adjusts the apparent width of the reverb sound. It does not just mix the output signal to mono, but also controls internal stereo linking and channel cross-feeding. Starting at 0% (mono), increasing the stereo width slowly makes the reverb true stereo. At 50%, channel cross-feeding is at its maximum: a sound that originates in one input channel, reverberates with an equal amount in both channels. Increasing the value from 50% up, slowly re-introduces stereo placement, up to a 100% where channels operate completely independent (i.e. multi-mono). Above 100%, the side signal is amplified which can be useful to achieve better mono compatibility.
The Mix knob controls the dry/wet balance of the final reverb sound. If you are using Pro-R as a send effect, you should set it to 100%.
The small Lock Mix button underneath the Mix knob locks the mix setting to its current value while loading presets, so you can more easily compare different settings. When locked, you can still manually change the mix or automate it if desired, and the mix value is always saved with your session. If you change the Lock Mix setting, new Pro-R instances will automatically pick up the new setting.